Add file-transfer module: multipart limits, filename handling, Range downloads, streaming under -Xmx64m, S3 presigned URLs

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01VRLbHYdXVEBzGVhYq3pz4q
Add rest-client-test module: @RestClientTest on Boot 4.1, Jackson 3 by default, and the RestClient-vs-RestTemplate root-URI matching trap (post #49 )
2026-10-17 15:41:24 +00:00 · 2026-10-08 16:40:51 +00:00 · 2026-10-08 12:35:04 +00:00 · 2026-10-08 11:52:08 +00:00 · 2026-10-08 09:40:13 +00:00 · 2026-10-08 06:19:52 +00:00
713 changed files with 21264 additions and 0 deletions
@@ -9,6 +9,7 @@ files.
 | Directory | Article | What it demonstrates |
 |---|---|---|
 | [`hexagonal/`](hexagonal) | [Hexagonal Architecture (Ports and Adapters) in Spring Boot 4](https://ankurm.com/hexagonal-architecture-ports-and-adapters-spring-boot-4/) | a 4-module Maven reactor that makes "the core has no Spring dependency" something `mvn dependency:tree` proves rather than a naming convention, testing the core with zero Spring context, and a Spring Boot 4 test-slice-artifact split (`@DataJpaTest`, `@WebMvcTest`, `TestRestTemplate`) hit and fixed along the way |
 | [`actuator-in-production/`](actuator-in-production) | [Spring Boot Actuator in Production](https://ankurm.com/spring-boot-actuator-production-endpoints-security-health-indicators/) | endpoint exposure defaults, securing Actuator, custom health indicators and how they hang |
 | [`spring-boot-startup-time/`](spring-boot-startup-time) | [Why Your Spring Boot App Takes 8 Seconds to Start](spring-boot-startup-time/post/post.md) | `BufferingApplicationStartup`, JFR startup events, self time vs total time, the classpath-scan tax, the JDK 25 AOT cache |
 | [`configuration-properties/`](configuration-properties) | [@ConfigurationProperties vs @Value in Spring Boot 4](https://ankurm.com/) | relaxed binding measured three ways, record constructor binding, validation, IDE metadata generation |
@@ -31,6 +32,27 @@ files.
 | [`custom-validation/`](custom-validation) | [Custom Validation in Spring Boot: Beyond the Basics!](https://ankurm.com/custom-validation-in-spring-boot-beyond-the-basics/) | the `javax.validation` to `jakarta.validation` namespace fix Boot 3 already required, Jakarta Validation 3.1's record-validation clarification proven on both field- and class-level custom constraints, a record validation failure's empty 400 body by default, and what `spring.mvc.problemdetails.enabled` does and does not fix |
 | [`etag-caching/`](etag-caching) | [Mastering Cache Control with ETag in Spring Boot RESTful APIs](https://ankurm.com/etag-cache-control-rest-api-spring-boot/) | `spring-boot-starter-web`'s own POM now reading "deprecated in favor of spring-boot-starter-webmvc", `ShallowEtagHeaderFilter` and `WebRequest.checkNotModified()` re-verified unchanged on Spring Framework 7, deep cache vs shallow cache, and conditional `PUT` with `If-Match` as optimistic locking |
 | [`restclient-basic-auth/`](restclient-basic-auth) | [Spring Boot RestTemplate with Basic Auth: A Modern Guide](https://ankurm.com/spring-boot-resttemplate-with-basic-auth-a-modern-guide/) | RestClient with Basic Auth two ways against a real embedded server, `{noop}` passwords confirmed to emit no runtime warning at all, `spring-boot-starter-restclient` as its own required Boot 4 module, and the `RestClient.exchange()` trap covered in depth by the [RestTemplate to RestClient migration guide](https://ankurm.com/resttemplate-to-restclient-migration-guide/) |
 | [`core-di/`](core-di) | [Dependency Injection in Spring Boot 4: Constructor vs Setter vs Field (and Why Field Injection Hurts)](https://ankurm.com/spring-boot-4-dependency-injection-constructor-setter-field/) and [@Autowired Explained: By-Type Resolution, @Qualifier, @Primary, ObjectProvider and List Injection](https://ankurm.com/spring-autowired-qualifier-primary-objectprovider-list-injection/) | one `OrderService` in three injection styles built with plain `new`, a field-injected dependency used in a constructor, circular dependencies in plain Spring vs Boot with the real failure report, `@Lazy` injecting a proxy, and the `@Autowired` resolution ladder read from Spring 7.0.9 bytecode (name match beats `@Priority`), plus the empty-collection trap that only bites field and setter injection |
 | [`core-beans/`](core-beans) | [Spring Bean Scopes: Singleton, Prototype, Request, Session and the Prototype-in-Singleton Trap](https://ankurm.com/spring-bean-scopes-singleton-prototype-request-session-prototype-in-singleton-trap/) [Spring Bean Lifecycle in Boot 4: @PostConstruct, InitializingBean, SmartLifecycle and Shutdown Order](https://ankurm.com/spring-bean-lifecycle-postconstruct-smartlifecycle-shutdown-order/) and [Circular Dependencies in Spring Boot 4: Why Startup Fails and 4 Ways to Fix It](https://ankurm.com/spring-boot-4-circular-dependencies-startup-fails-4-fixes/) | instance counts per scope, five fixes for a prototype inside a singleton, request scope without a proxy failing at start-up, every lifecycle callback in order, `@PostConstruct` running before the proxy exists, `SmartLifecycle` phases measured, a `SmartLifecycle` at the default phase stopping before Tomcat has drained, and the circular-dependency start-up failure reproduced with four fixes |
 | [`custom-starter/`](custom-starter) | [Write Your Own Spring Boot 4 Starter: Auto-Configuration, @Conditional and Properties](https://ankurm.com/write-your-own-spring-boot-4-starter-auto-configuration-conditional-properties/) | a starter split into an auto-configuration module and a starter, the `AutoConfiguration.imports` registration, `@ConditionalOn*` conditions, configuration metadata, and tests with `ApplicationContextRunner` |
 | [`core-events/`](core-events) | [Spring Application Events: @EventListener, @TransactionalEventListener and Async Events](https://ankurm.com/spring-application-events-eventlistener-transactionaleventlistener-async/) | publishing and consuming events, listener ordering, conditional listeners, `AFTER_COMMIT` behaviour proven with a rollback, and async listeners |
 | [`multi-datasource/`](multi-datasource) | [Multiple DataSources in Spring Boot 4 with Spring Data JPA](https://ankurm.com/multiple-datasources-spring-boot-4-spring-data-jpa/) | two H2 databases each with its own `DataSource`, Flyway, `EntityManagerFactory` and transaction manager, six ways of getting the wiring wrong, plain vs named `@Transactional`, and `ChainedTransactionManager` under a failing commit |
 | [`i18n/`](i18n) | [Internationalization (i18n) in Spring Boot 4: MessageSource, LocaleResolver and Localized ProblemDetail](https://ankurm.com/spring-boot-4-internationalization-messagesource-localeresolver-problemdetail/) | English, Marathi and Hindi message bundles, `Accept-Language` vs a cookie resolver, apostrophes and Devanagari digits in `MessageFormat`, the JVM default locale as a hidden fallback, localized validation messages and `ProblemDetail` titles |
 | [`aot-cache/`](aot-cache) | [Faster Spring Boot Startup with the JDK AOT Cache (JEP 514/515): Benchmarks vs CDS and Native](https://ankurm.com/spring-boot-jdk-aot-cache-jep-514-515-startup-benchmarks/) | the JDK 25 AOT cache trained two ways, against a plain JVM, AppCDS, Spring's own AOT output and a GraalVM native image (ten interleaved rounds each), first-request latency, 24 cases where the cache silently stops applying (jar, timestamp, JVM build, ZGC, compact headers), `-XX:AOTMode=on`, Docker layer arithmetic |
 | [`kotlin/`](kotlin) | [Kotlin with Spring Boot 4.1: Null Safety, Coroutines, and What Java Developers Get Wrong](https://ankurm.com/) | Kotlin 2.3.21 (Boot 4.1.1's own managed version, not the latest GA), the real `@Configuration class may not be final` and `@Bean method must not be private or final` failures without the allopen/noarg `spring`/`jpa` compiler plugins, `suspend fun`/`Flow<T>` controller methods proven to still resume off a Tomcat thread under plain `spring-boot-starter-webmvc`, a JSpecify `@NullMarked` Java method that still NPEs at runtime because the contract isn't runtime-checked, and `TestRestTemplate` confirmed absent from Boot 4.1's `spring-boot-test` jar |
 | [`testing-no-containers/`](testing-no-containers) | [Testing Spring Boot 4 Without Containers: WireMock, MockWebServer and @MockitoBean](https://ankurm.com/) | `@MockBean`'s total removal proven with a real `javac` failure, `@MockitoBean`/`@MockitoSpyBean` context-cache behavior proven with real `org.springframework.test.context.cache` DEBUG log lines, WireMock fault injection against a real `RestClient`, a real `NoClassDefFoundError` from mixing `wiremock` with `wiremock-jetty12` (fixed with `wiremock-standalone`), and MockWebServer's `SocketEffect.ShutdownConnection` for genuinely severing a connection mid-response |
 | [`rest-test-client/`](rest-test-client) | [RestTestClient in Spring Framework 7: Testing REST APIs End-to-End (vs MockMvcTester)](https://ankurm.com/resttestclient-spring-framework-7-end-to-end-testing/) | one fluent `RestTestClient` API proven across `bindToController`, `bindTo(mockMvc)`, `bindToApplicationContext` and `bindToServer`; `RestTestClient`, `TestRestTemplate` and `@WebMvcTest` confirmed relocated into new Spring Boot 4 modules by unzipping the real jars; two distinct real failures for the two now-separate `@AutoConfigureRestTestClient`/`@AutoConfigureTestRestTemplate` annotations; and the JDK `HttpClient` Boot picks for `bindToServer` caught transparently decoding gzip and hiding `Content-Encoding`, verified against `curl` and against the older `SimpleClientHttpRequestFactory` |
 | [`file-transfer/`](file-transfer) | [File Upload and Download in Spring Boot 4: Multipart, Streaming and S3 Presigned URLs](https://ankurm.com/file-upload-download-spring-boot-4-multipart-streaming-s3-presigned-urls/) | multipart limits enforced by Tomcat (and ignored by `MockMvc`), the client-controlled filename, `Range` downloads, a 200 MB download and 150 MB upload under `-Xmx64m`, and S3 presigned URLs checked against a local SigV4 verifier (not a real S3) |
 `core-di`, `core-beans`, `custom-starter`, `core-events`, `multi-datasource`, `i18n`, `aot-cache`, `kotlin`, `testing-no-containers`, `rest-test-client` and `hexagonal` are the exception: they have **no `docs/NN-topic.md` chapter folder**. Their deeper material lives in
 collapsible sections inside the articles themselves. Where their captured output sits is not
 uniform, and is worth checking per module rather than assuming: `core-di`, `core-beans`,
 `custom-starter`, `core-events`, `multi-datasource`, `i18n` and `aot-cache` keep it in a
 top-level `output/` directory (`hexagonal` is also the one multi-module reactor in this repo,
 so its output sits one level deeper still, under each module: `core/output/`,
 `persistence-adapter/output/`, and so on) — but `kotlin`, `testing-no-containers` and
 `rest-test-client` still use `docs/output/`, same as the chaptered modules, just without the
 `docs/NN-topic.md` chapters themselves.
 Articles whose text is kept here rather than only on the blog have it under
 `<directory>/post/` — `post.md` for the body and `meta.md` for the title, excerpt and
@@ -0,0 +1,6 @@
 target/
 *.aot
 *.aotconf
 *.jsa
 work/
 work-run.log
@@ -0,0 +1,70 @@
 # aot-cache: the JDK 25 AOT cache on a Spring Boot 4.1 service
 Companion project for **[Faster Spring Boot Startup with the JDK AOT Cache (JEP 514/515): Benchmarks vs CDS and Native](https://ankurm.com/spring-boot-jdk-aot-cache-jep-514-515-startup-benchmarks/)**
 on [ankurm.com](https://ankurm.com). Everything the article quotes is a file in [`output/`](output), regenerated by
 [`run.sh`](run.sh). The explanation lives in the article; this directory holds the code and the raw transcripts.
 There is no `docs/` folder on purpose: the deeper material sits in collapsible sections of the article itself.
 ## The service
 A small Spring Boot 4.1.1 web application, built to have the ingredients of a typical service and no more:
 Spring MVC and Jackson (`POST /orders` with a JSON body), Bean Validation (a record with `@Email`, `@Pattern`,
 `@Min`/`@Max`), the actuator health endpoint, and an in-memory store. No database. Sources are under
 [`src/main/java/com/ankurm/aotcache/`](src/main/java/com/ankurm/aotcache).
 ## Versions
 | | |
 |---|---|
 | Spring Boot | 4.1.1 (Spring Framework 7.0.9, Tomcat 11.0.24, Jackson 3.1.5, Hibernate Validator 9.1.3) |
 | JDK for the article | Temurin 25.0.4.1 (LTS) |
 | JDK for the comparison | Temurin 27+35 |
 | GraalVM (native image) | Community Edition 25.0.2+10.1 |
 | Machine | 2 vCPU, 8 GB, Linux |
 ## What is here
 | Script | What it does | Output |
 |---|---|---|
 | [`scripts/prepare.sh`](scripts/prepare.sh) | Builds the plain jar, a jar with Spring's own AOT output, a jar after a one-line change; extracts them | [`00-prepare.txt`](output/00-prepare.txt), [`00-environment.txt`](output/00-environment.txt) |
 | [`scripts/native.sh`](scripts/native.sh) | Compiles the GraalVM native image | [`03-native-build.txt`](output/03-native-build.txt) |
 | [`scripts/train.sh`](scripts/train.sh) | The training runs: AppCDS, AOT cache (context-only and with traffic, with and without Spring AOT, on JDK 27, under ZGC) | [`01-training.txt`](output/01-training.txt) |
 | [`scripts/startup.sh`](scripts/startup.sh) | 12 configurations x 10 interleaved rounds: time to ready, Boot's own figure, first request, resident memory | [`02-startup.txt`](output/02-startup.txt) |
 | [`scripts/mismatch.sh`](scripts/mismatch.sh) | 24 ways the cache and the run can disagree, and what the JVM says and does | [`04-mismatch.txt`](output/04-mismatch.txt) |
 | [`scripts/layers.sh`](scripts/layers.sh) | Docker layer arithmetic without Docker: which layers change on a one-line edit, sizes, gzipped sizes | [`05-layers.txt`](output/05-layers.txt) |
 | [`scripts/sample.sh`](scripts/sample.sh) | A transcript of the service's endpoints | [`06-sample-endpoints.txt`](output/06-sample-endpoints.txt) |
 | [`docker/Dockerfile`](docker/Dockerfile) | A layered image with the cache trained in the final stage (**not built here**: no Docker daemon) | |
 ## Headline result
 Median of ten runs, milliseconds from starting the process to the first `200` from `GET /ping`
 ([`output/02-startup.txt`](output/02-startup.txt)):
 | Configuration | Ready | First `POST /orders` |
 |---|---|---|
 | Plain JVM, extracted jar | 3,920 | 173 |
 | AppCDS | 2,583 | 164 |
 | AOT cache, context-only training | 2,022 | 143 |
 | AOT cache, training with traffic | 1,949 | 68 |
 | AOT cache + Spring AOT, training with traffic | 1,436 | 89 |
 | GraalVM native image | 133 | 5.3 |
 ## Running it
 Needs JDK 25, JDK 27, a GraalVM for JDK 25 and Maven; `scripts/env.sh` shows where they are looked up and each can be
 overridden with `JDK25`, `JDK27` and `GRAALVM`. The measurement scripts assume Linux and `curl`, and need the machine to
 themselves.
 ```console
 cd aot-cache
 ./run.sh                 # about 35 minutes; the native build is 5 of them
 ROUNDS=3 ./run.sh        # a quick pass
 ```
 ## Caveats
 * One small service on one 2-CPU virtual machine. The ratios are what to take away, not the milliseconds.
 * No database and no JPA, so the service is smaller than most real ones; a larger classpath usually gains more from the cache.
 * JEP 515 (method profiles) is part of the cache on JDK 25 and cannot be switched off separately, so its own contribution was not isolated.
 * The Docker image was not built; the layer figures come from extracting the jar's layers and comparing files.
 * `openjdk.org/jeps` returned HTTP 403 to the tooling used, so JEP claims come from running the JDKs and from secondary sources named in the article.
@@ -0,0 +1,21 @@
 # NOT BUILT OR RUN while writing the article: the sandbox has no Docker daemon. The commands inside it are the ones
 # scripts/train.sh and scripts/mismatch.sh ran (extract, AOTCacheOutput, AOTCache); the layer arithmetic is in
 # output/05-layers.txt. Treat the file as a starting point and measure it in your own registry.
 #
 # Build:  mvn -DskipTests package && docker build -f docker/Dockerfile -t aot-cache .
 FROM eclipse-temurin:25-jdk AS extract
 WORKDIR /build
 COPY target/app.jar app.jar
 RUN java -Djarmode=tools -jar app.jar extract --layers --destination extracted
 # The final image is also where the cache is trained: the cache records the exact JVM build and the exact
 # jar files (size and modification time), so it must be created by the JVM that will use it, after the last COPY.
 FROM eclipse-temurin:25-jre
 WORKDIR /application
 COPY --from=extract /build/extracted/dependencies/ ./
 COPY --from=extract /build/extracted/spring-boot-loader/ ./
 COPY --from=extract /build/extracted/snapshot-dependencies/ ./
 COPY --from=extract /build/extracted/application/ ./
 RUN java -XX:AOTCacheOutput=app.aot -Dspring.context.exit=onRefresh -jar app.jar
 ENTRYPOINT ["java", "-XX:AOTCache=app.aot", "-jar", "app.jar"]
@@ -0,0 +1,24 @@
 # machine
 cpus: 2   memory: 8032 MB   kernel: 6.18.44-fc-v37
 # JDK 25 (the JVM the article is about)
 openjdk version "25.0.4.1" 2026-08-18 LTS
 OpenJDK Runtime Environment Temurin-25.0.4.1+1 (build 25.0.4.1+1-LTS)
 OpenJDK 64-Bit Server VM Temurin-25.0.4.1+1 (build 25.0.4.1+1-LTS, mixed mode, sharing)
 # JDK 27 (the comparison)
 openjdk version "27" 2026-09-15
 OpenJDK Runtime Environment Temurin-27+35 (build 27+35)
 OpenJDK 64-Bit Server VM Temurin-27+35 (build 27+35, mixed mode, sharing)
 # GraalVM (native image)
 native-image 25.0.2 2026-01-20
 GraalVM Runtime Environment GraalVM CE 25.0.2+10.1 (build 25.0.2+10-jvmci-b01)
 # libraries
 hibernate-validator-9.1.3.Final
 jackson-databind-3.1.5
 spring-boot-4.1.1
 spring-core-7.0.9
 spring-webmvc-7.0.9
 tomcat-embed-core-11.0.24
@@ -0,0 +1,14 @@
 == build: plain jar (mvn package)
 == build: jar with Spring AOT output (mvn -Pnative package; this does NOT compile a native image)
 initializers in plain jar:       0
 initializers in Spring AOT jar:  1
 == extract both jars (java -Djarmode=tools -jar app.jar extract)
 /home/claude/spring-boot-demo/aot-cache/work/ext:
 app.jar
 lib
 /home/claude/spring-boot-demo/aot-cache/work/ext-springaot:
 app.jar
 lib
 == build: the same service after a one-line change (the unit price in OrderService), for the mismatch and layer checks
 edited: 20:        BigDecimal unit = BigDecimal.valueOf(5_99, 2);
@@ -0,0 +1,17 @@
 # training runs (JDK 25.0.4.1 unless noted); wall time includes JVM start, context start and cache creation
 AppCDS  (ArchiveClassesAtExit)       4741 ms   appcds.jsa (38 MB)
 AOT cache, fat jar, context-only     8219 ms   fat.aot (56 MB)
 AOT cache, context-only training     7916 ms   refresh.aot (59 MB)
 AOT cache, traffic training         10157 ms   traffic.aot (66 MB)
 AOT cache + Spring AOT, context-only   7164 ms   springaot.aot (57 MB)
 AOT cache + Spring AOT, traffic      8733 ms   springaot-traffic.aot (64 MB)
 AOT cache on JDK 27, context-only    9292 ms   refresh27.aot (62 MB)
 AOT cache on JDK 27, trained under ZGC   9426 ms   zgc27.aot (62 MB)
 # what the JVM said at warning level while writing the context-only AOT cache (count, then the distinct kinds)
 warning lines: 122
     96 [warning][aot] Skipping <class>: Unsupported location
      4 [warning][aot] Skipping <class>: Unlinked class not supported by AOTClassLinking
      4 [warning][aot] Skipping <class>: Failed verification
      3 [warning][aot] Skipping <class>: JFR event class
      2 [warning][aot] Skipping <class>: Not in loaded state
@@ -0,0 +1,138 @@
 # 12 configurations x 10 rounds; one unrecorded warm-up round first (so cache files are in the page cache)
 == medians of 10 runs (min..max in brackets), milliseconds; rss in MB
 configuration                    ready (exec->200)    Boot 'Started in'    1st POST /orders     next 50 (median)   RSS
 1 jvm-fat-jar                    4630.5 [4281..4931]  3683.5 [3455..3954]  204.0 [166.6..230.7] 4.5                194.0
 2 jvm-extracted                  3919.5 [3486..4018]  3242.0 [2890..3400]  173.3 [146.6..191.7] 4.8                189.0
 3 jvm+spring-aot                 3162.0 [2991..3500]  2552.0 [2419..2907]  201.8 [165.3..254.3] 4.5                183.0
 4 appcds                         2582.5 [2436..2730]  2181.0 [2022..2330]  164.3 [133.9..170.2] 4.8                195.0
 5 aot-cache fat-jar              3247.0 [3096..3507]  2553.5 [2432..2787]  156.6 [144.9..186.6] 4.7                235.0
 6 aot-cache context-only         2021.5 [1948..2253]  1568.0 [1495..1785]  142.8 [116.1..160.0] 4.8                218.0
 7 aot-cache traffic              1948.5 [1777..2142]  1623.5 [1406..1775]  67.7 [47.5..101.8]   4.5                198.5
 8 aot-cache+spring-aot           1588.5 [1482..1674]  1120.5 [1030..1218]  146.6 [131.4..163.9] 4.5                188.0
 9 aot-cache+spring-aot traffic   1436.0 [1372..1651]  1069.0 [1015..1280]  89.3 [65.9..113.0]   4.2                184.0
 10 jdk27 plain                   3779.5 [3595..4205]  3122.5 [2919..3408]  164.8 [139.9..176.8] 4.6                234.0
 11 jdk27 aot-cache               1983.0 [1840..2181]  1571.5 [1444..1763]  138.2 [117.9..191.0] 4.2                195.5
 12 native image                  133.0 [127..171]     101.5 [90..133]      5.3 [4.6..6.0]       1.0                120.0
 == every run
 1 jvm-fat-jar  1  ready=4407  started=3460  first=201.9  second=6.4  next50=3.2  rss=186
 2 jvm-extracted  1  ready=3486  started=2890  first=187.6  second=7.4  next50=4.0  rss=189
 3 jvm+spring-aot  1  ready=3111  started=2495  first=203.0  second=8.9  next50=4.5  rss=189
 4 appcds  1  ready=2535  started=2133  first=166.6  second=12.8  next50=4.8  rss=190
 5 aot-cache fat-jar  1  ready=3096  started=2432  first=157.2  second=11.4  next50=4.3  rss=234
 6 aot-cache context-only  1  ready=1948  started=1555  first=133.0  second=6.0  next50=3.4  rss=211
 7 aot-cache traffic  1  ready=1984  started=1642  first=47.5  second=5.5  next50=4.5  rss=200
 8 aot-cache+spring-aot  1  ready=1482  started=1030  first=153.1  second=7.2  next50=4.4  rss=189
 9 aot-cache+spring-aot traffic  1  ready=1372  started=1057  first=73.2  second=11.0  next50=3.5  rss=184
 10 jdk27 plain  1  ready=3595  started=2919  first=165.6  second=13.0  next50=4.5  rss=224
 11 jdk27 aot-cache  1  ready=1890  started=1517  first=135.2  second=7.1  next50=3.4  rss=195
 12 native image  1  ready=127  started=90  first=4.6  second=0.9  next50=0.7  rss=120
 1 jvm-fat-jar  2  ready=4495  started=3692  first=166.6  second=20.1  next50=4.2  rss=195
 2 jvm-extracted  2  ready=3725  started=3117  first=173.6  second=7.5  next50=4.1  rss=191
 3 jvm+spring-aot  2  ready=3121  started=2522  first=199.1  second=10.0  next50=4.1  rss=188
 4 appcds  2  ready=2496  started=2104  first=166.9  second=8.3  next50=4.2  rss=200
 5 aot-cache fat-jar  2  ready=3250  started=2579  first=186.6  second=17.7  next50=4.6  rss=239
 6 aot-cache context-only  2  ready=2029  started=1568  first=140.9  second=16.2  next50=3.5  rss=218
 7 aot-cache traffic  2  ready=1840  started=1506  first=76.5  second=9.3  next50=3.4  rss=200
 8 aot-cache+spring-aot  2  ready=1550  started=1070  first=131.4  second=14.7  next50=5.0  rss=188
 9 aot-cache+spring-aot traffic  2  ready=1444  started=1070  first=78.5  second=5.8  next50=4.2  rss=185
 10 jdk27 plain  2  ready=3767  started=3121  first=164.1  second=8.4  next50=3.9  rss=219
 11 jdk27 aot-cache  2  ready=1844  started=1444  first=124.8  second=6.0  next50=4.2  rss=196
 12 native image  2  ready=171  started=133  first=5.6  second=1.4  next50=1.0  rss=120
 1 jvm-fat-jar  3  ready=4281  started=3455  first=188.9  second=7.0  next50=4.1  rss=187
 2 jvm-extracted  3  ready=3944  started=3315  first=163.8  second=8.1  next50=4.0  rss=191
 3 jvm+spring-aot  3  ready=2991  started=2419  first=254.3  second=9.6  next50=4.4  rss=177
 4 appcds  3  ready=2436  started=2049  first=170.2  second=7.7  next50=4.5  rss=198
 5 aot-cache fat-jar  3  ready=3127  started=2478  first=156.1  second=8.6  next50=4.4  rss=231
 6 aot-cache context-only  3  ready=2020  started=1601  first=149.9  second=12.2  next50=4.7  rss=219
 7 aot-cache traffic  3  ready=1777  started=1406  first=65.2  second=6.2  next50=4.2  rss=200
 8 aot-cache+spring-aot  3  ready=1547  started=1066  first=134.8  second=6.7  next50=5.5  rss=190
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 11 jdk27 aot-cache  3  ready=1840  started=1494  first=125.0  second=9.8  next50=4.1  rss=196
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 1 jvm-fat-jar  4  ready=4665  started=3675  first=190.9  second=7.0  next50=4.6  rss=196
 2 jvm-extracted  4  ready=3837  started=3188  first=191.7  second=7.7  next50=5.2  rss=190
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 4 appcds  4  ready=2450  started=2022  first=168.7  second=11.6  next50=3.7  rss=193
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 6 aot-cache context-only  4  ready=2012  started=1495  first=126.3  second=11.3  next50=4.0  rss=205
 7 aot-cache traffic  4  ready=1899  started=1537  first=70.1  second=12.4  next50=5.5  rss=186
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 9 aot-cache+spring-aot traffic  4  ready=1472  started=1144  first=65.9  second=10.6  next50=4.2  rss=184
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 2 jvm-extracted  5  ready=4018  started=3400  first=180.4  second=10.5  next50=5.2  rss=196
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 1 jvm-fat-jar  6  ready=4524  started=3575  first=196.3  second=8.5  next50=4.4  rss=195
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 4 appcds  6  ready=2730  started=2330  first=152.3  second=7.5  next50=5.0  rss=197
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 10 jdk27 plain  6  ready=4103  started=3408  first=168.7  second=7.7  next50=5.1  rss=249
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 1 jvm-fat-jar  7  ready=4787  started=3913  first=224.4  second=10.0  next50=4.7  rss=197
 2 jvm-extracted  7  ready=3899  started=3237  first=165.2  second=8.8  next50=5.4  rss=189
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 4 appcds  7  ready=2592  started=2172  first=162.1  second=9.6  next50=4.8  rss=205
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 7 aot-cache traffic  7  ready=2111  started=1771  first=100.5  second=13.5  next50=4.5  rss=200
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 1 jvm-fat-jar  8  ready=4608  started=3729  first=211.0  second=8.0  next50=5.0  rss=192
 2 jvm-extracted  8  ready=4008  started=3345  first=180.4  second=8.2  next50=4.5  rss=181
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 4 appcds  8  ready=2573  started=2199  first=161.4  second=8.6  next50=5.0  rss=192
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 2 jvm-extracted  9  ready=3728  started=3060  first=173.0  second=8.9  next50=4.8  rss=182
 3 jvm+spring-aot  9  ready=3266  started=2544  first=200.6  second=10.7  next50=5.0  rss=182
 4 appcds  9  ready=2596  started=2244  first=136.5  second=7.9  next50=5.2  rss=192
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 1 jvm-fat-jar  10  ready=4931  started=3954  first=206.1  second=8.8  next50=4.8  rss=193
 2 jvm-extracted  10  ready=3940  started=3247  first=146.6  second=12.8  next50=4.8  rss=185
 3 jvm+spring-aot  10  ready=3203  started=2587  first=206.7  second=8.9  next50=4.6  rss=187
 4 appcds  10  ready=2607  started=2190  first=169.4  second=7.8  next50=5.2  rss=193
 5 aot-cache fat-jar  10  ready=3495  started=2699  first=144.9  second=8.1  next50=3.7  rss=241
 6 aot-cache context-only  10  ready=2023  started=1568  first=134.5  second=32.5  next50=4.5  rss=218
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 8 aot-cache+spring-aot  10  ready=1556  started=1095  first=150.2  second=9.2  next50=4.3  rss=188
 9 aot-cache+spring-aot traffic  10  ready=1575  started=1213  first=107.0  second=6.5  next50=4.0  rss=184
 10 jdk27 plain  10  ready=4010  started=3356  first=156.0  second=7.2  next50=4.4  rss=233
 11 jdk27 aot-cache  10  ready=2016  started=1573  first=171.6  second=7.8  next50=4.5  rss=196
 12 native image  10  ready=133  started=103  first=5.4  second=1.2  next50=1.0  rss=120
@@ -0,0 +1,9 @@
 # GraalVM: native-image 25.0.2 2026-01-20
 21,929 types,  31,331 fields, and  99,355 methods found reachable
 36.0s (11.7% of total time) in 2209 GCs | Peak RSS: 4.70GB | CPU load: 1.86
 Finished generating 'aot-cache' in 5m 6s.
 BUILD SUCCESS
 Total time:  05:18 min
 /home/claude/spring-boot-demo/aot-cache/work/aot-cache-native 99 MB
 /home/claude/spring-boot-demo/aot-cache/work/app.jar 22 MB
 build wall time: 320 s
@@ -0,0 +1,152 @@
 # cache: /home/claude/spring-boot-demo/aot-cache/work/refresh.aot, trained on JDK 25.0.4.1, extracted layout, default GC (G1), 2 CPUs
 == control: the same JVM, the same jar, the same path
   result:  started, ready after 1987 ms   (Started AotCacheApplication in 1.538 seconds)
   log:     (nothing at warning or error level)
 == the application jar was rebuilt after a one-line code change, default AOTMode=auto
   result:  started, ready after 4124 ms   (Started AotCacheApplication in 3.453 seconds)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'app.jar', timestamp has changed, size has changed
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] Unable to map shared spaces
 == the same, with -XX:AOTMode=on
   result:  did not start (exit code 1)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'app.jar', timestamp has changed, size has changed
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] unrecoverable error
 == a dependency jar has a different modification time (same bytes)
   result:  started, ready after 3865 ms   (Started AotCacheApplication in 3.201 seconds)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'lib/spring-core-7.0.9.jar', timestamp has changed
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] Unable to map shared spaces
 == the same files copied with plain cp (bytes and path layout identical, timestamps new)
   result:  started, ready after 4013 ms   (Started AotCacheApplication in 3.361 seconds)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'app.jar', timestamp has changed
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] Unable to map shared spaces
 == the application directory was moved after training (same bytes, different path)
   result:  started, ready after 2005 ms   (Started AotCacheApplication in 1.542 seconds)
   log:     (nothing at warning or error level)
 == cache trained on the fat jar, run from the extracted layout
   result:  started, ready after 3900 ms   (Started AotCacheApplication in 3.262 seconds)
   log:    [warning][aot] This file is not the one used while building the AOT cache: 'app.jar', size has changed
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] shared class paths mismatch (hint: enable -Xlog:class+path=info to diagnose the failure)
   log:    [error  ][aot] Unable to map shared spaces
 == JDK 25's cache used by JDK 27
   result:  started, ready after 4221 ms   (Started AotCacheApplication in 3.537 seconds)
   log:    [warning][aot] The AOT cache version 0x13 does not match the required version 0x14.
   log:    [warning][aot] The AOT cache has the wrong version.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [warning][aot] The AOT cache version 0x13 does not match the required version 0x14.
 == the same, with -XX:AOTMode=on
   result:  did not start (exit code 1)
   log:    [warning][aot] The AOT cache version 0x13 does not match the required version 0x14.
   log:    [warning][aot] The AOT cache has the wrong version.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [warning][aot] The AOT cache version 0x13 does not match the required version 0x14.
 == -XX:+UseCompactObjectHeaders added at run time only (JDK 25)
   result:  started, ready after 4138 ms   (Started AotCacheApplication in 3.446 seconds)
   log:    [warning][aot] Unable to use AOT cache.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [error  ][aot] Unable to map shared spaces
 == a different collector at run time: -XX:+UseSerialGC
   result:  started, ready after 1916 ms   (Started AotCacheApplication in 1.516 seconds)
   log:     (nothing at warning or error level)
 == a different collector at run time: -XX:+UseParallelGC
   result:  started, ready after 1957 ms   (Started AotCacheApplication in 1.473 seconds)
   log:     (nothing at warning or error level)
 == a different collector at run time: -XX:+UseZGC
   result:  started, ready after 3981 ms   (Started AotCacheApplication in 3.347 seconds)
   log:    [warning][aot] Unable to use AOT cache.
 [                    ] The saved state of UseCompressedOops and UseCompressedClassPointers is different from runtime, CDS will be disabled.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [error  ][aot] Unable to map shared spaces
 == a different heap size at run time: -Xmx256m
   result:  started, ready after 2058 ms   (Started AotCacheApplication in 1.602 seconds)
   log:     (nothing at warning or error level)
 == a cache file that does not exist
   result:  started, ready after 4113 ms   (Started AotCacheApplication in 3.451 seconds)
   log:    [error][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error][aot] Loading static archive failed.
   log:    [error][aot] Unable to map shared spaces
 == a cache file that does not exist, with -XX:AOTMode=on
   result:  did not start (exit code 1)
   log:    [error][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error][aot] Loading static archive failed.
   log:    [error][aot] Unable to map shared spaces
 # and on JDK 27, whose cache was trained under the default collector (G1):
 == JDK 27, cache from JDK 27 (control)
   result:  started, ready after 1955 ms   (Started AotCacheApplication in 1.547 seconds)
   log:     (nothing at warning or error level)
 == JDK 27, -XX:+UseZGC at run time
   result:  started, ready after 4158 ms   (Started AotCacheApplication in 3.502 seconds)
   log:    [warning][aot] Unable to use AOT cache.
 [                    ] The saved state of UseCompressedOops (1) is different from runtime (0), CDS will be disabled.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [error  ][aot] Unable to map shared spaces
 == JDK 27, -XX:+UseSerialGC at run time
   result:  started, ready after 2103 ms   (Started AotCacheApplication in 1.672 seconds)
   log:     (nothing at warning or error level)
 == JDK 27, -XX:-UseCompactObjectHeaders at run time
   result:  started, ready after 3906 ms   (Started AotCacheApplication in 3.163 seconds)
   log:    [warning][aot] Unable to use AOT cache.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [warning][aot] Unable to use AOT cache.
   log:    [error  ][aot] Loading static archive failed.
 # why ZGC is different: ask the JVM (-Xlog:aot=info) why it refused the G1-trained cache
 == JDK 27, -XX:+UseZGC with the G1-trained cache, -Xlog:aot=info
   result:  started, ready after 3885 ms   (Started AotCacheApplication in 3.258 seconds)
   log:    [info][aot] The AOT cache was created with UseCompressedOops = 1, UseCompactObjectHeaders = 1
   log:    [warning][aot] Unable to use AOT cache.
 [                    ] The saved state of UseCompressedOops (1) is different from runtime (0), CDS will be disabled.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
 == JDK 27, cache trained under ZGC, run under ZGC
   result:  started, ready after 1988 ms   (Started AotCacheApplication in 1.554 seconds)
   log:     (nothing at warning or error level)
 == JDK 27, cache trained under ZGC, run under G1 (compressed oops on again)
   result:  started, ready after 3869 ms   (Started AotCacheApplication in 3.199 seconds)
   log:    [warning][aot] Unable to use AOT cache.
 [                    ] The saved state of UseCompressedOops (0) is different from runtime (1), CDS will be disabled.
   log:    [error  ][aot] An error has occurred while processing the AOT cache. Run with -Xlog:aot for details.
   log:    [error  ][aot] Loading static archive failed.
   log:    [warning][aot] Unable to use AOT cache.
 == JDK 27, cache trained under ZGC, run under G1 with -XX:-UseCompressedOops
   result:  started, ready after 2018 ms   (Started AotCacheApplication in 1.534 seconds)
   log:     (nothing at warning or error level)
@@ -0,0 +1,17 @@
 # java -Djarmode=tools -jar app.jar extract --layers   (the layer order Spring Boot's Dockerfile support uses)
 layer                          KB    gzip KB files
 dependencies                22878      20490 47
 spring-boot-loader              0          0 0
 snapshot-dependencies           0          0 0
 application                     8          7 1
 # the AOT cache from the training run (context-only), for scale
 refresh.aot                 61016      15362
 # change one line of application code (the unit price in OrderService, built by prepare.sh), extract again
 layer                  before         after          verdict
 dependencies           81a2cb4f9f5c   81a2cb4f9f5c   identical: reused from cache/registry
 spring-boot-loader     abcfa6a9d4df   abcfa6a9d4df   identical: reused from cache/registry
 snapshot-dependencies  abcfa6a9d4df   abcfa6a9d4df   identical: reused from cache/registry
 application            4ecdea8230c6   19563974ba7b   CHANGED: rebuilt and pushed
 AOT cache: trained against the previous jar, so it is stale for the new one (see output/04-mismatch.txt); it must be regenerated after the application layer
@@ -0,0 +1,12 @@
 $ curl localhost:18110/ping
 ok [HTTP 200]
 $ curl -H 'Content-Type: application/json' -d '{"customer":"[email protected]","sku":"ABC-1234","quantity":3}' localhost:18110/orders
 {"id":1,"customer":"[email protected]","sku":"ABC-1234","quantity":3,"total":14.97,"createdAt":"2026-09-24T16:35:45.259486118Z"} [HTTP 201]
 $ curl localhost:18110/orders/1
 {"id":1,"customer":"[email protected]","sku":"ABC-1234","quantity":3,"total":14.97,"createdAt":"2026-09-24T16:35:45.259486118Z"} [HTTP 200]
 $ curl -H 'Content-Type: application/json' -d '{"customer":"bad","sku":"x","quantity":0}' localhost:18110/orders
 {"timestamp":"2026-09-24T16:35:45.351Z","status":400,"error":"Bad Request","path":"/orders"} [HTTP 400]
 $ curl localhost:18110/orders/99
 [HTTP 404]
 $ curl localhost:18110/actuator/health
 {"groups":["liveness","readiness"],"status":"UP"} [HTTP 200]
@@ -0,0 +1,62 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>4.1.1</version>
    <relativePath/>
  </parent>
  <groupId>com.ankurm</groupId>
  <artifactId>aot-cache</artifactId>
  <version>1.0.0</version>
  <name>aot-cache</name>
  <description>The JDK 25 AOT cache (JEP 514/515) on a Spring Boot 4.1 service, measured against a plain JVM, AppCDS and a GraalVM native image</description>
  <properties>
    <java.version>25</java.version>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-webmvc</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-validation</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
  </dependencies>
  <build>
    <finalName>app</finalName>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
  <profiles>
    <profile>
      <id>native</id>
      <build>
        <plugins>
          <plugin>
            <groupId>org.graalvm.buildtools</groupId>
            <artifactId>native-maven-plugin</artifactId>
          </plugin>
        </plugins>
      </build>
    </profile>
  </profiles>
 </project>
@@ -0,0 +1,15 @@
 #!/usr/bin/env bash
 # Regenerates everything under output/. Takes about 30 minutes; the native build alone is about 5.
 # Needs JDK 25, JDK 27, a GraalVM for JDK 25 and Maven (paths: scripts/env.sh). Use the machine for nothing else while it runs.
 cd "$(dirname "$0")" || exit 1
 source scripts/env.sh
 ROUNDS=${ROUNDS:-10}
 mkdir -p output
 bash scripts/prepare.sh                          > output/00-prepare.txt     2>&1
 bash scripts/environment.sh                      > output/00-environment.txt 2>&1
 bash scripts/native.sh                           > output/03-native-build.txt 2>&1
 bash scripts/train.sh                            > output/01-training.txt    2>&1
 bash scripts/startup.sh "$ROUNDS"                > output/02-startup.txt     2> "$WORK/startup.err"
 bash scripts/mismatch.sh                         > output/04-mismatch.txt    2>&1
 bash scripts/layers.sh                           > output/05-layers.txt      2>&1
 bash scripts/sample.sh                           > output/06-sample-endpoints.txt 2>&1
@@ -0,0 +1,14 @@
 #!/usr/bin/env bash
 # Where the JDKs and GraalVM live. Override with environment variables; nothing else is hard-coded.
 : "${JDK25:=/tmp/tools/j25/jdk-25.0.4.1+1}"
 : "${JDK27:=/tmp/tools/j27/jdk-27+35}"
 : "${GRAALVM:=$(ls -d /tmp/tools/graal/graalvm-community* 2>/dev/null | head -1)}"
 export JDK25 JDK27 GRAALVM
 ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 WORK="$ROOT/work"          # generated jars, caches and logs (git-ignored)
 OUT="$ROOT/output"         # transcripts that the article quotes (committed)
 export ROOT WORK OUT
 # Maven may need proxy/trust-store options that must not leak into the JVM runs being measured.
 MVN_JTO="${JAVA_TOOL_OPTIONS:-}"
 unset JAVA_TOOL_OPTIONS JDK_JAVA_OPTIONS _JAVA_OPTIONS
 mvn_run() { JAVA_TOOL_OPTIONS="$MVN_JTO" "$@"; }
@@ -0,0 +1,7 @@
 #!/usr/bin/env bash
 source "$(dirname "$0")/env.sh"
 echo "# machine"; echo "cpus: $(nproc)   memory: $(free -m | awk '/Mem:/ {print $2}') MB   kernel: $(uname -r)"
 echo; echo "# JDK 25 (the JVM the article is about)"; "$JDK25/bin/java" -version 2>&1
 echo; echo "# JDK 27 (the comparison)"; "$JDK27/bin/java" -version 2>&1
 echo; echo "# GraalVM (native image)"; "$GRAALVM/bin/native-image" --version 2>&1 | head -2
 echo; echo "# libraries"; ls "$WORK/ext/lib" | grep -E '^(spring-boot|spring-core|spring-webmvc|tomcat-embed-core|jackson-databind|hibernate-validator)-[0-9]' | sed 's/\.jar$//'
@@ -0,0 +1,34 @@
 #!/usr/bin/env bash
 # Docker layer arithmetic without a Docker daemon: which layers of the extracted application change when one line of
 # code changes, how big each layer is (uncompressed, and gzipped as a registry would store it), and where the AOT
 # cache falls. A layer is "a directory tree"; two builds share a layer when the tree is byte-identical.
 source "$(dirname "$0")/env.sh"
 cd "$ROOT"
 layer_sum() {   # dir -> one hash over every file's path and contents
  ( cd "$1" && find . -type f | LC_ALL=C sort | xargs sha256sum | sha256sum | cut -c1-12 )
 }
 gz_kb() { tar -C "$1" -cf - . 2>/dev/null | gzip -6 | wc -c | awk '{printf "%d", $1/1024}'; }
 kb()    { find "$1" -type f -printf '%s\n' | awk '{s+=$1} END{printf "%d", s/1024}'; }
 echo "# java -Djarmode=tools -jar app.jar extract --layers   (the layer order Spring Boot's Dockerfile support uses)"
 rm -rf "$WORK/layers-a" "$WORK/layers-b"
 "$JDK25/bin/java" -Djarmode=tools -jar "$WORK/app.jar" extract --layers --destination "$WORK/layers-a" >/dev/null
 printf '%-22s %10s %10s %s\n' layer "KB" "gzip KB" "files"
 for d in dependencies spring-boot-loader snapshot-dependencies application; do
  printf '%-22s %10s %10s %s\n' "$d" "$(kb "$WORK/layers-a/$d")" "$(gz_kb "$WORK/layers-a/$d")" "$(find "$WORK/layers-a/$d" -type f | wc -l)"
 done
 echo
 echo "# the AOT cache from the training run (context-only), for scale"
 printf '%-22s %10s %10s\n' "refresh.aot" "$(( $(stat -c %s "$WORK/refresh.aot") / 1024 ))" "$(gzip -6 -c "$WORK/refresh.aot" | wc -c | awk '{printf "%d", $1/1024}')"
 echo
 echo "# change one line of application code (the unit price in OrderService, built by prepare.sh), extract again"
 "$JDK25/bin/java" -Djarmode=tools -jar "$WORK/app-changed.jar" extract --layers --destination "$WORK/layers-b" >/dev/null
 printf '%-22s %-14s %-14s %s\n' layer "before" "after" "verdict"
 for d in dependencies spring-boot-loader snapshot-dependencies application; do
  a=$(layer_sum "$WORK/layers-a/$d"); b=$(layer_sum "$WORK/layers-b/$d")
  printf '%-22s %-14s %-14s %s\n' "$d" "$a" "$b" "$([ "$a" = "$b" ] && echo "identical: reused from cache/registry" || echo "CHANGED: rebuilt and pushed")"
 done
 echo "AOT cache: trained against the previous jar, so it is stale for the new one (see output/04-mismatch.txt); it must be regenerated after the application layer"
@@ -0,0 +1,46 @@
 #!/usr/bin/env bash
 # Start / probe / stop helpers shared by the measurement scripts.
 source "$(dirname "${BASH_SOURCE[0]}")/env.sh"
 PORT=18110
 BODY='{"customer":"[email protected]","sku":"ABC-1234","quantity":3}'
 now_ms() { echo $(( $(date +%s%N) / 1000000 )); }
 # start_app WORKDIR LOGFILE cmd args...  -> sets APP_PID (the java/native process itself, thanks to exec)
 start_app() {
  local wd=$1 log=$2; shift 2
  ( cd "$wd" && exec "$@" ) > "$log" 2>&1 &
  APP_PID=$!
 }
 # wait_ready  -> 0 when GET /ping answers 200 within 60 s
 wait_ready() {
  local i
  for i in $(seq 1 3000); do
    curl -sf -o /dev/null --max-time 2 "localhost:$PORT/ping" && return 0
    kill -0 "$APP_PID" 2>/dev/null || return 1
    sleep 0.02
  done
  return 1
 }
 stop_app() {
  kill "$APP_PID" 2>/dev/null
  wait "$APP_PID" 2>/dev/null
  return 0
 }
 # ms_of SECONDS -> milliseconds with one decimal
 ms_of() { awk -v s="$1" 'BEGIN{printf "%.1f", s*1000}'; }
 # post_order -> prints curl's time_total in ms
 post_order() {
  ms_of "$(curl -s -o /dev/null -w '%{time_total}' -H 'Content-Type: application/json' -d "$BODY" "localhost:$PORT/orders")"
 }
 get_order() { ms_of "$(curl -s -o /dev/null -w '%{time_total}' "localhost:$PORT/orders/1")"; }
 rss_mb() { awk '/VmRSS/ {printf "%d", $2/1024}' "/proc/$APP_PID/status"; }
 median() { sort -n | awk '{a[NR]=$1} END{ if (NR==0) {print "n/a"; exit} if (NR%2) printf "%s", a[(NR+1)/2]; else printf "%.1f", (a[NR/2]+a[NR/2+1])/2 }'; }
 minmax() { sort -n | awk 'NR==1{lo=$1} {hi=$1} END{printf "%s..%s", lo, hi}'; }
@@ -0,0 +1,80 @@
 #!/usr/bin/env bash
 # What happens when the cache does not match the run. Each case starts the service with a cache that was made
 # under different conditions, and prints (1) what the JVM logged about the cache, (2) how long start-up took.
 #   -XX:AOTMode=auto is the default: use the cache if it is valid, otherwise carry on without it.
 #   -XX:AOTMode=on : refuse to start if the cache cannot be used.
 source "$(dirname "$0")/lib.sh"
 J25=$JDK25/bin/java; J27=$JDK27/bin/java
 run_case() {   # title, workdir, cmd...   (runs once with -Xlog:aot=warning so the cache's complaints show up)
  local title=$1 wd=$2; shift 2
  local t0 log="$WORK/mismatch.log"
  echo "== $title"
  t0=$(now_ms)
  start_app "$wd" "$log" "$@" --server.port=$PORT
  if wait_ready; then
    echo "   result:  started, ready after $(( $(now_ms) - t0 )) ms   ($(grep -o 'Started [A-Za-z]* in [0-9.]* seconds' "$log"))"
    stop_app
  else
    wait "$APP_PID" 2>/dev/null
    echo "   result:  did not start (exit code $?)"
  fi
  grep -E '\[(warning|error)[ ]*\]\[(aot|cds)|saved state of|created with' "$log" | grep -v 'Skipping' | head -5 | sed -E 's/^\[[0-9.]+s\]/   log:    /' | cut -c1-170
  [ -z "$(grep -E '\[(warning|error)[ ]*\]\[(aot|cds)' "$log" | grep -v Skipping)" ] && echo "   log:     (nothing at warning or error level)"
  echo
 }
 echo "# cache: $WORK/refresh.aot, trained on JDK 25.0.4.1, extracted layout, default GC (G1), 2 CPUs"
 echo
 run_case "control: the same JVM, the same jar, the same path" "$WORK/ext" "$J25" -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 # 1. the jar changed after training
 # (cp -a everywhere below: plain cp gives every file a new modification time, which the cache checks - see the timestamp case)
 rm -rf "$WORK/ext-changed"; cp -a "$WORK/ext" "$WORK/ext-changed"
 "$JDK25/bin/java" -Djarmode=tools -jar "$WORK/app-changed.jar" extract --destination "$WORK/changed-tmp" >/dev/null
 cp "$WORK/changed-tmp/app-changed.jar" "$WORK/ext-changed/app.jar"; rm -rf "$WORK/changed-tmp"   # only the application jar differs
 run_case "the application jar was rebuilt after a one-line code change, default AOTMode=auto" "$WORK/ext-changed" "$J25" -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 run_case "the same, with -XX:AOTMode=on" "$WORK/ext-changed" "$J25" -XX:AOTMode=on -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 # 2. a dependency jar changed
 rm -rf "$WORK/ext-dep"; cp -a "$WORK/ext" "$WORK/ext-dep"
 ( cd "$WORK/ext-dep/lib" && f=$(ls spring-core-*.jar) && touch -d '2001-01-01' "$f" )
 run_case "a dependency jar has a different modification time (same bytes)" "$WORK/ext-dep" "$J25" -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 # 2b. only a copy, with fresh timestamps (what `cp -r` or a re-extract does)
 rm -rf "$WORK/ext-copy"; cp -r "$WORK/ext" "$WORK/ext-copy"
 run_case "the same files copied with plain cp (bytes and path layout identical, timestamps new)" "$WORK/ext-copy" "$J25" -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 # 3. moved to another directory
 rm -rf "$WORK/moved"; mkdir -p "$WORK/moved"; cp -a "$WORK/ext" "$WORK/moved/app-dir"
 run_case "the application directory was moved after training (same bytes, different path)" "$WORK/moved/app-dir" "$J25" -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 # 4. fat jar cache used with the extracted layout
 run_case "cache trained on the fat jar, run from the extracted layout" "$WORK/ext" "$J25" -XX:AOTCache="$WORK/fat.aot" -jar app.jar
 # 5. different JVM
 run_case "JDK 25's cache used by JDK 27" "$WORK/ext" "$J27" -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 run_case "the same, with -XX:AOTMode=on" "$WORK/ext" "$J27" -XX:AOTMode=on -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 # 6. flags that change what the cache holds
 run_case "-XX:+UseCompactObjectHeaders added at run time only (JDK 25)" "$WORK/ext" "$J25" -XX:+UseCompactObjectHeaders -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 run_case "a different collector at run time: -XX:+UseSerialGC" "$WORK/ext" "$J25" -XX:+UseSerialGC -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 run_case "a different collector at run time: -XX:+UseParallelGC" "$WORK/ext" "$J25" -XX:+UseParallelGC -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 run_case "a different collector at run time: -XX:+UseZGC" "$WORK/ext" "$J25" -XX:+UseZGC -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 run_case "a different heap size at run time: -Xmx256m" "$WORK/ext" "$J25" -Xmx256m -XX:AOTCache="$WORK/refresh.aot" -jar app.jar
 run_case "a cache file that does not exist" "$WORK/ext" "$J25" -XX:AOTCache="$WORK/nonexistent.aot" -jar app.jar
 run_case "a cache file that does not exist, with -XX:AOTMode=on" "$WORK/ext" "$J25" -XX:AOTMode=on -XX:AOTCache="$WORK/nonexistent.aot" -jar app.jar
 echo "# and on JDK 27, whose cache was trained under the default collector (G1):"
 echo
 run_case "JDK 27, cache from JDK 27 (control)" "$WORK/ext" "$J27" -XX:AOTCache="$WORK/refresh27.aot" -jar app.jar
 run_case "JDK 27, -XX:+UseZGC at run time" "$WORK/ext" "$J27" -XX:+UseZGC -XX:AOTCache="$WORK/refresh27.aot" -jar app.jar
 run_case "JDK 27, -XX:+UseSerialGC at run time" "$WORK/ext" "$J27" -XX:+UseSerialGC -XX:AOTCache="$WORK/refresh27.aot" -jar app.jar
 run_case "JDK 27, -XX:-UseCompactObjectHeaders at run time" "$WORK/ext" "$J27" -XX:-UseCompactObjectHeaders -XX:AOTCache="$WORK/refresh27.aot" -jar app.jar
 echo "# why ZGC is different: ask the JVM (-Xlog:aot=info) why it refused the G1-trained cache"
 echo
 run_case "JDK 27, -XX:+UseZGC with the G1-trained cache, -Xlog:aot=info" "$WORK/ext" "$J27" -XX:+UseZGC -Xlog:aot=info -XX:AOTCache="$WORK/refresh27.aot" -jar app.jar
 run_case "JDK 27, cache trained under ZGC, run under ZGC" "$WORK/ext" "$J27" -XX:+UseZGC -XX:AOTCache="$WORK/zgc27.aot" -jar app.jar
 run_case "JDK 27, cache trained under ZGC, run under G1 (compressed oops on again)" "$WORK/ext" "$J27" -XX:AOTCache="$WORK/zgc27.aot" -jar app.jar
 run_case "JDK 27, cache trained under ZGC, run under G1 with -XX:-UseCompressedOops" "$WORK/ext" "$J27" -XX:-UseCompressedOops -XX:AOTCache="$WORK/zgc27.aot" -jar app.jar
@@ -0,0 +1,11 @@
 #!/usr/bin/env bash
 # Builds the GraalVM native image of the same service (no reflection tricks: the app has none). Takes minutes.
 source "$(dirname "$0")/env.sh"
 cd "$ROOT"; mkdir -p "$WORK"
 t0=$(date +%s)
 JAVA_HOME=$GRAALVM mvn_run mvn -B -DskipTests -Pnative native:compile > "$WORK/native-build.log" 2>&1
 rc=$?
 echo "# GraalVM: $("$GRAALVM/bin/native-image" --version 2>&1 | head -1)"
 grep -E "types, .* fields, and .* methods found reachable|Peak RSS|Finished generating|BUILD (SUCCESS|FAILURE)|Total time" "$WORK/native-build.log" | sed -E 's/^\[INFO\] //; s/^ +//'
 [ $rc -eq 0 ] && cp "target/aot-cache" "$WORK/aot-cache-native" && ls -l "$WORK/aot-cache-native" "$WORK/app.jar" | awk '{printf "%-30s %d MB\n", $NF, $5/1048576}'
 echo "build wall time: $(( $(date +%s) - t0 )) s"
@@ -0,0 +1,32 @@
 #!/usr/bin/env bash
 # Builds everything the measurements need under work/: the plain jar, a jar with Spring's own AOT output,
 # the extracted layout, an AppCDS archive and the AOT caches. Prints what it built and how big each artifact is.
 source "$(dirname "$0")/env.sh"
 set -e
 cd "$ROOT"
 rm -rf "$WORK"; mkdir -p "$WORK"
 echo "== build: plain jar (mvn package)"
 rm -rf "$ROOT/target"      # a stale target/ would carry Spring AOT output from an earlier -Pnative build into the plain jar
 JAVA_HOME=$JDK25 mvn_run mvn -q -B -DskipTests package > "$WORK/build-plain.log" 2>&1
 cp target/app.jar "$WORK/app.jar"
 rm -rf "$ROOT/target"
 echo "== build: jar with Spring AOT output (mvn -Pnative package; this does NOT compile a native image)"
 JAVA_HOME=$JDK25 mvn_run mvn -q -B -DskipTests -Pnative package > "$WORK/build-springaot.log" 2>&1
 cp target/app.jar "$WORK/app-springaot.jar"
 echo "initializers in plain jar:       $(unzip -l "$WORK/app.jar" | grep -c '__ApplicationContextInitializer')"
 echo "initializers in Spring AOT jar:  $(unzip -l "$WORK/app-springaot.jar" | grep -c '__ApplicationContextInitializer')"
 echo "== extract both jars (java -Djarmode=tools -jar app.jar extract)"
 "$JDK25/bin/java" -Djarmode=tools -jar "$WORK/app.jar" extract --destination "$WORK/ext" >/dev/null
 "$JDK25/bin/java" -Djarmode=tools -jar "$WORK/app-springaot.jar" extract --destination "$WORK/ext-springaot" >/dev/null
 mv "$WORK/ext-springaot/app-springaot.jar" "$WORK/ext-springaot/app.jar"   # the launcher jar keeps its lib/ Class-Path
 ls "$WORK/ext" "$WORK/ext-springaot"
 echo "== build: the same service after a one-line change (the unit price in OrderService), for the mismatch and layer checks"
 mkdir -p "$WORK/changed-src"
 cp -r pom.xml src "$WORK/changed-src/"
 sed -i 's/BigDecimal.valueOf(4_99, 2)/BigDecimal.valueOf(5_99, 2)/' "$WORK/changed-src/src/main/java/com/ankurm/aotcache/OrderService.java"
 grep -n 'valueOf(5_99' "$WORK/changed-src/src/main/java/com/ankurm/aotcache/OrderService.java" | sed 's/^/edited: /'
 ( cd "$WORK/changed-src" && JAVA_HOME=$JDK25 mvn_run mvn -q -B -DskipTests package > "$WORK/build-changed.log" 2>&1 )
 cp "$WORK/changed-src/target/app.jar" "$WORK/app-changed.jar"
@@ -0,0 +1,17 @@
 #!/usr/bin/env bash
 # A transcript of the service's own endpoints, so the reader knows what the training run's traffic is.
 source "$(dirname "$0")/lib.sh"
 start_app "$WORK/ext" "$WORK/sample.log" "$JDK25/bin/java" -jar app.jar --server.port=$PORT
 wait_ready || { echo "did not start"; exit 1; }
 show() {   # print the command the way a shell would need it typed, then run it
  printf '$'; for a in "$@"; do case $a in *[' {}"']*) printf " '%s'" "$a";; *) printf ' %s' "$a";; esac; done; echo
  "$@" -s -w ' [HTTP %{http_code}]\n'
 }
 show curl "localhost:$PORT/ping"
 show curl -H 'Content-Type: application/json' -d "$BODY" "localhost:$PORT/orders"
 show curl "localhost:$PORT/orders/1"
 show curl -H 'Content-Type: application/json' -d '{"customer":"bad","sku":"x","quantity":0}' "localhost:$PORT/orders"
 show curl "localhost:$PORT/orders/99"
 show curl "localhost:$PORT/actuator/health"
 stop_app
 exit 0
@@ -0,0 +1,61 @@
 #!/usr/bin/env bash
 # Startup and first-request latency for every configuration. Configurations are run in interleaved rounds
 # (round 1 runs all of them once, then round 2, ...) so slow drift on a shared machine hits all of them alike.
 #   scripts/startup.sh [ROUNDS]          default 10
 source "$(dirname "$0")/lib.sh"
 ROUNDS=${1:-10}
 LOG="$WORK/startup-runs.txt"; : > "$LOG"
 declare -A WD CMD
 labels=()
 add_cfg() { local l=$1 wd=$2; shift 2; labels+=("$l"); WD[$l]=$wd; CMD[$l]="$*"; }
 J25=$JDK25/bin/java; J27=$JDK27/bin/java
 add_cfg "1 jvm-fat-jar"                 "$WORK"            "$J25 -jar app.jar"
 add_cfg "2 jvm-extracted"               "$WORK/ext"        "$J25 -jar app.jar"
 add_cfg "3 jvm+spring-aot"              "$WORK/ext-springaot" "$J25 -Dspring.aot.enabled=true -jar app.jar"
 add_cfg "4 appcds"                      "$WORK/ext"        "$J25 -XX:SharedArchiveFile=$WORK/appcds.jsa -jar app.jar"
 add_cfg "5 aot-cache fat-jar"           "$WORK"            "$J25 -XX:AOTCache=$WORK/fat.aot -jar app.jar"
 add_cfg "6 aot-cache context-only"      "$WORK/ext"        "$J25 -XX:AOTCache=$WORK/refresh.aot -jar app.jar"
 add_cfg "7 aot-cache traffic"           "$WORK/ext"        "$J25 -XX:AOTCache=$WORK/traffic.aot -jar app.jar"
 add_cfg "8 aot-cache+spring-aot"        "$WORK/ext-springaot" "$J25 -Dspring.aot.enabled=true -XX:AOTCache=$WORK/springaot.aot -jar app.jar"
 add_cfg "9 aot-cache+spring-aot traffic" "$WORK/ext-springaot" "$J25 -Dspring.aot.enabled=true -XX:AOTCache=$WORK/springaot-traffic.aot -jar app.jar"
 add_cfg "10 jdk27 plain"                 "$WORK/ext"        "$J27 -jar app.jar"
 add_cfg "11 jdk27 aot-cache"            "$WORK/ext"        "$J27 -XX:AOTCache=$WORK/refresh27.aot -jar app.jar"
 [ -x "$WORK/aot-cache-native" ] && add_cfg "12 native image"  "$WORK" "$WORK/aot-cache-native"
 one_run() {  # label round
  local l=$1 r=$2 t0 ready started first second med50 rss
  t0=$(now_ms)
  start_app "${WD[$l]}" "$WORK/run.log" ${CMD[$l]} --server.port=$PORT
  if ! wait_ready; then echo "RUN|$l|$r|FAILED" >> "$LOG"; stop_app; return; fi
  ready=$(( $(now_ms) - t0 ))
  started=$(grep -o 'Started [A-Za-z]* in [0-9.]* seconds' "$WORK/run.log" | awk '{print $4*1000}')
  first=$(post_order); second=$(get_order)
  med50=$(for i in $(seq 1 50); do post_order; echo; done | grep . | median)
  rss=$(rss_mb)
  echo "RUN|$l|$r|ready=$ready|started=${started:-n/a}|first=$first|second=$second|next50=$med50|rss=$rss" >> "$LOG"
  stop_app; sleep 0.5
 }
 echo "# ${#labels[@]} configurations x $ROUNDS rounds; one unrecorded warm-up round first (so cache files are in the page cache)"
 for l in "${labels[@]}"; do one_run "$l" 0; done; : > "$LOG"
 for r in $(seq 1 $ROUNDS); do
  for l in "${labels[@]}"; do one_run "$l" "$r"; done
  echo "round $r done" >&2
 done
 field() { grep -F "RUN|$1|" "$LOG" | grep -o "$2=[0-9.]*" | cut -d= -f2; }
 echo
 echo "== medians of $ROUNDS runs (min..max in brackets), milliseconds; rss in MB"
 printf '%-32s %-20s %-20s %-20s %-18s %s\n' "configuration" "ready (exec->200)" "Boot 'Started in'" "1st POST /orders" "next 50 (median)" "RSS"
 for l in "${labels[@]}"; do
  f=$(grep -cF "RUN|$l|" "$LOG"); ok=$(grep -F "RUN|$l|" "$LOG" | grep -vc FAILED)
  cell() { local v; v=$(field "$l" "$1"); printf '%-20s ' "$(echo "$v" | median) [$(echo "$v" | minmax)]"; }
  printf '%-32s ' "$l"; cell ready; cell started; cell first; printf '%-18s ' "$(field "$l" next50 | median)"; printf '%s' "$(field "$l" rss | median)"
  [ "$ok" != "$f" ] && printf '   (%s of %s runs failed)' $((f-ok)) $f
  echo
 done
 echo
 echo "== every run"
 sed 's/^RUN|//; s/|/  /g' "$LOG"
@@ -0,0 +1,59 @@
 #!/usr/bin/env bash
 # The training runs: one per cache flavour. Prints how long each took, how big the artifact is, and what the
 # JVM logged at warning level while writing it.  Needs scripts/prepare.sh to have run.
 source "$(dirname "$0")/lib.sh"
 exercise() {   # the traffic a "real" training run sends: success, validation failure, 404, actuator
  for i in 1 2 3 4 5; do post_order >/dev/null; done
  get_order >/dev/null
  curl -s -o /dev/null -H 'Content-Type: application/json' -d '{"customer":"bad","sku":"x","quantity":0}' "localhost:$PORT/orders"
  curl -s -o /dev/null "localhost:$PORT/orders/99"
  curl -s -o /dev/null "localhost:$PORT/actuator/health"
 }
 report() { # label file t0
  printf '%-34s %6d ms   %s (%s MB)\n' "$1" $(( $(now_ms) - $3 )) "$(basename "$2")" "$(( $(stat -c %s "$2") / 1048576 ))"
 }
 echo "# training runs (JDK 25.0.4.1 unless noted); wall time includes JVM start, context start and cache creation"
 t0=$(now_ms)
 ( cd "$WORK/ext" && "$JDK25/bin/java" -XX:ArchiveClassesAtExit="$WORK/appcds.jsa" -Dspring.context.exit=onRefresh -jar app.jar ) > "$WORK/train-appcds.log" 2>&1
 report "AppCDS  (ArchiveClassesAtExit)" "$WORK/appcds.jsa" $t0
 t0=$(now_ms)
 "$JDK25/bin/java" -XX:AOTCacheOutput="$WORK/fat.aot" -Dspring.context.exit=onRefresh -jar "$WORK/app.jar" > "$WORK/train-fat.log" 2>&1
 report "AOT cache, fat jar, context-only" "$WORK/fat.aot" $t0
 t0=$(now_ms)
 ( cd "$WORK/ext" && "$JDK25/bin/java" -XX:AOTCacheOutput="$WORK/refresh.aot" -Dspring.context.exit=onRefresh -jar app.jar ) > "$WORK/train-refresh.log" 2>&1
 report "AOT cache, context-only training" "$WORK/refresh.aot" $t0
 t0=$(now_ms)
 start_app "$WORK/ext" "$WORK/train-traffic.log" "$JDK25/bin/java" -XX:AOTCacheOutput="$WORK/traffic.aot" -jar app.jar --server.port=$PORT
 wait_ready && exercise
 kill -TERM "$APP_PID"; wait "$APP_PID" 2>/dev/null
 report "AOT cache, traffic training" "$WORK/traffic.aot" $t0
 t0=$(now_ms)
 ( cd "$WORK/ext-springaot" && "$JDK25/bin/java" -Dspring.aot.enabled=true -XX:AOTCacheOutput="$WORK/springaot.aot" -Dspring.context.exit=onRefresh -jar app.jar ) > "$WORK/train-springaot.log" 2>&1
 report "AOT cache + Spring AOT, context-only" "$WORK/springaot.aot" $t0
 t0=$(now_ms)
 start_app "$WORK/ext-springaot" "$WORK/train-springaot-traffic.log" "$JDK25/bin/java" -Dspring.aot.enabled=true -XX:AOTCacheOutput="$WORK/springaot-traffic.aot" -jar app.jar --server.port=$PORT
 wait_ready && exercise
 kill -TERM "$APP_PID"; wait "$APP_PID" 2>/dev/null
 report "AOT cache + Spring AOT, traffic" "$WORK/springaot-traffic.aot" $t0
 t0=$(now_ms)
 ( cd "$WORK/ext" && "$JDK27/bin/java" -XX:AOTCacheOutput="$WORK/refresh27.aot" -Dspring.context.exit=onRefresh -jar app.jar ) > "$WORK/train-refresh27.log" 2>&1
 report "AOT cache on JDK 27, context-only" "$WORK/refresh27.aot" $t0
 t0=$(now_ms)
 ( cd "$WORK/ext" && "$JDK27/bin/java" -XX:+UseZGC -XX:AOTCacheOutput="$WORK/zgc27.aot" -Dspring.context.exit=onRefresh -jar app.jar ) > "$WORK/train-zgc27.log" 2>&1
 report "AOT cache on JDK 27, trained under ZGC" "$WORK/zgc27.aot" $t0
 echo
 echo "# what the JVM said at warning level while writing the context-only AOT cache (count, then the distinct kinds)"
 grep -c '\[warning\]\[aot\]' "$WORK/train-refresh.log" | sed 's/^/warning lines: /'
 grep '\[warning\]\[aot\]' "$WORK/train-refresh.log" | sed -E 's/^\[[0-9.]+s\]//; s/(Skipping) [^ ]+:/\1 <class>:/' | sort | uniq -c | sort -rn | head -5
@@ -0,0 +1,12 @@
 package com.ankurm.aotcache;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
 public class AotCacheApplication {
    public static void main(String[] args) {
        SpringApplication.run(AotCacheApplication.class, args);
    }
 }
@@ -0,0 +1,14 @@
 package com.ankurm.aotcache;
 import jakarta.validation.constraints.Email;
 import jakarta.validation.constraints.Max;
 import jakarta.validation.constraints.Min;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.Pattern;
 /** The request body of POST /orders. Bean Validation and Jackson both have to work on it. */
 public record NewOrder(
        @NotBlank @Email String customer,
        @NotBlank @Pattern(regexp = "[A-Z]{3}-[0-9]{4}") String sku,
        @Min(1) @Max(1000) int quantity) {
 }
@@ -0,0 +1,8 @@
 package com.ankurm.aotcache;
 import java.math.BigDecimal;
 import java.time.Instant;
 /** A stored order. */
 public record Order(long id, String customer, String sku, int quantity, BigDecimal total, Instant createdAt) {
 }
@@ -0,0 +1,38 @@
 package com.ankurm.aotcache;
 import java.net.URI;
 import jakarta.validation.Valid;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RestController;
@RestController
 public class OrderController {
    private final OrderService service;
    public OrderController(OrderService service) {
        this.service = service;
    }
    @GetMapping("/ping")
    public String ping() {
        return "ok";
    }
    @PostMapping("/orders")
    public ResponseEntity<Order> create(@Valid @RequestBody NewOrder body) {
        Order o = service.create(body);
        return ResponseEntity.created(URI.create("/orders/" + o.id())).body(o);
    }
    @GetMapping("/orders/{id}")
    public ResponseEntity<Order> get(@PathVariable long id) {
        return service.find(id).map(ResponseEntity::ok).orElseGet(() -> ResponseEntity.notFound().build());
    }
 }
@@ -0,0 +1,29 @@
 package com.ankurm.aotcache;
 import java.math.BigDecimal;
 import java.time.Instant;
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicLong;
 import org.springframework.stereotype.Service;
@Service
 public class OrderService {
    private final AtomicLong ids = new AtomicLong();
    private final Map<Long, Order> orders = new ConcurrentHashMap<>();
    public Order create(NewOrder in) {
        long id = ids.incrementAndGet();
        BigDecimal unit = BigDecimal.valueOf(4_99, 2);
        Order o = new Order(id, in.customer(), in.sku(), in.quantity(), unit.multiply(BigDecimal.valueOf(in.quantity())), Instant.now());
        orders.put(id, o);
        return o;
    }
    public Optional<Order> find(long id) {
        return Optional.ofNullable(orders.get(id));
    }
 }
@@ -0,0 +1,2 @@
 spring.application.name=aot-cache
 management.endpoints.web.exposure.include=health
@@ -0,0 +1 @@
 target/
@@ -0,0 +1,13 @@
 # batch-5-to-6: Spring Batch 5 to 6 on Spring Boot 3.5 to 4.1
 Companion code for the ankurm.com post "Spring Batch 5 to 6 Migration Guide".
 | Folder | What it is |
 |---|---|
 | `legacy/` | A one-job app on Boot 3.5.16 / Batch 5.2.6 (JDK 21) using the Batch 5 API |
 | `migrated/` | The same app on Boot 4.1.1 / Batch 6.0.5 (JDK 25) using the Batch 6 API |
 | `scripts/run-all.sh` | Builds the intermediate stages from `legacy/` and regenerates every file in `output/` |
 | `output/` | Transcripts: compile errors, startup failure, deprecation warnings, the silent listener change, and the final run |
 Batch 6.0.5 is the latest GA; 6.1.0-M1 and 6.1.0-M2 are milestones and are not tested here.
 Tested on 28 September 2026.
@@ -0,0 +1,21 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>3.5.16</version>
    <relativePath/>
  </parent>
  <groupId>com.ankurm</groupId>
  <artifactId>batch-legacy</artifactId>
  <version>1.0.0</version>
  <properties><java.version>21</java.version></properties>
  <dependencies>
    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-batch</artifactId></dependency>
    <dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency>
    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
    <dependency><groupId>org.springframework.batch</groupId><artifactId>spring-batch-test</artifactId><scope>test</scope></dependency>
  </dependencies>
  <build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build>
 </project>
@@ -0,0 +1,14 @@
 package com.ankurm.batch;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.ConfigurableApplicationContext;
@SpringBootApplication
 public class App {
    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(App.class, args);
        ctx.getBean(JobRunner.class).run();
        ctx.close();
    }
 }
@@ -0,0 +1,55 @@
 package com.ankurm.batch;
 import java.util.List;
 import org.springframework.batch.core.ChunkListener;
 import org.springframework.batch.core.Job;
 import org.springframework.batch.core.Step;
 import org.springframework.batch.core.job.builder.JobBuilder;
 import org.springframework.batch.core.repository.JobRepository;
 import org.springframework.batch.core.scope.context.ChunkContext;
 import org.springframework.batch.core.step.builder.StepBuilder;
 import org.springframework.batch.item.ItemReader;
 import org.springframework.batch.item.ItemWriter;
 import org.springframework.batch.item.support.ListItemReader;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.transaction.PlatformTransactionManager;
@Configuration
 public class BatchConfig {
    @Bean
    ItemReader<Integer> reader() {
        return new ListItemReader<>(List.of(1, 2, 3, 4, 5, 6, 7));
    }
    @Bean
    ItemWriter<String> writer() {
        return chunk -> System.out.println("WRITE " + chunk.getItems());
    }
    @Bean
    ChunkListener chunkListener() {
        return new ChunkListener() {
            @Override public void afterChunk(ChunkContext context) {
                System.out.println("CHUNK DONE, read so far=" + context.getStepContext().getStepExecution().getReadCount());
            }
        };
    }
    @Bean
    Step squareStep(JobRepository repo, PlatformTransactionManager tx, ChunkListener listener) {
        return new StepBuilder("squareStep", repo)
                .<Integer, String>chunk(3, tx)
                .reader(reader())
                .processor(i -> "sq" + (i * i))
                .writer(writer())
                .listener(listener)
                .build();
    }
    @Bean
    Job squareJob(JobRepository repo, Step squareStep) {
        return new JobBuilder("squareJob", repo).start(squareStep).build();
    }
 }
@@ -0,0 +1,33 @@
 package com.ankurm.batch;
 import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.Job;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.JobParameters;
 import org.springframework.batch.core.JobParametersBuilder;
 import org.springframework.batch.core.explore.JobExplorer;
 import org.springframework.batch.core.launch.JobLauncher;
 import org.springframework.stereotype.Component;
@Component
 public class JobRunner {
    private final JobLauncher launcher;
    private final JobExplorer explorer;
    private final Job job;
    public JobRunner(JobLauncher launcher, JobExplorer explorer, Job squareJob) {
        this.launcher = launcher; this.explorer = explorer; this.job = squareJob;
    }
    public void run() {
        try {
            JobParameters params = new JobParametersBuilder().addLong("run.id", 1L).toJobParameters();
            JobExecution exec = launcher.run(job, params);
            System.out.println("STATUS " + exec.getStatus() + " exit=" + exec.getExitStatus().getExitCode());
            System.out.println("INSTANCES " + explorer.getJobInstanceCount("squareJob"));
            System.out.println("DONE " + (exec.getStatus() == BatchStatus.COMPLETED));
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }
 }
@@ -0,0 +1,3 @@
 spring.batch.job.enabled=false
 spring.datasource.url=jdbc:h2:mem:legacy;DB_CLOSE_DELAY=-1
 spring.batch.jdbc.initialize-schema=always
@@ -0,0 +1,23 @@
 package com.ankurm.batch;
 import static org.assertj.core.api.Assertions.assertThat;
 import org.junit.jupiter.api.Test;
 import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.test.JobLauncherTestUtils;
 import org.springframework.batch.test.context.SpringBatchTest;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
@SpringBatchTest
 class JobTest {
    @Autowired JobLauncherTestUtils utils;
    @Test
    void jobCompletes() throws Exception {
        JobExecution exec = utils.launchJob();
        assertThat(exec.getStatus()).isEqualTo(BatchStatus.COMPLETED);
    }
 }
@@ -0,0 +1,22 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>4.1.1</version>
    <relativePath/>
  </parent>
  <groupId>com.ankurm</groupId>
  <artifactId>batch-migrated</artifactId>
  <version>1.0.0</version>
  <properties><java.version>25</java.version></properties>
  <dependencies>
    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-batch-jdbc</artifactId></dependency>
    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency>
    <dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency>
    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
    <dependency><groupId>org.springframework.batch</groupId><artifactId>spring-batch-test</artifactId><scope>test</scope></dependency>
  </dependencies>
  <build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build>
 </project>
@@ -0,0 +1,14 @@
 package com.ankurm.batch;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.ConfigurableApplicationContext;
@SpringBootApplication
 public class App {
    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(App.class, args);
        ctx.getBean(JobRunner.class).run();
        ctx.close();
    }
 }
@@ -0,0 +1,56 @@
 package com.ankurm.batch;
 import java.util.List;
 import org.springframework.batch.core.listener.ChunkListener;
 import org.springframework.batch.core.job.Job;
 import org.springframework.batch.core.step.Step;
 import org.springframework.batch.core.job.builder.JobBuilder;
 import org.springframework.batch.core.repository.JobRepository;
 import org.springframework.batch.core.step.builder.StepBuilder;
 import org.springframework.batch.infrastructure.item.Chunk;
 import org.springframework.batch.infrastructure.item.ItemReader;
 import org.springframework.batch.infrastructure.item.ItemWriter;
 import org.springframework.batch.infrastructure.item.support.ListItemReader;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.transaction.PlatformTransactionManager;
@Configuration
 public class BatchConfig {
    @Bean
    ItemReader<Integer> reader() {
        return new ListItemReader<>(List.of(1, 2, 3, 4, 5, 6, 7));
    }
    @Bean
    ItemWriter<String> writer() {
        return chunk -> System.out.println("WRITE " + chunk.getItems());
    }
    @Bean
    ChunkListener<Integer, String> chunkListener() {
        return new ChunkListener<>() {
            @Override public void afterChunk(Chunk<String> chunk) {
                System.out.println("CHUNK DONE, items in chunk=" + chunk.size());
            }
        };
    }
    @Bean
    Step squareStep(JobRepository repo, PlatformTransactionManager tx, ChunkListener<Integer, String> listener) {
        return new StepBuilder("squareStep", repo)
                .<Integer, String>chunk(3)
                .transactionManager(tx)
                .reader(reader())
                .processor(i -> "sq" + (i * i))
                .writer(writer())
                .listener(listener)
                .build();
    }
    @Bean
    Job squareJob(JobRepository repo, Step squareStep) {
        return new JobBuilder("squareJob", repo).start(squareStep).build();
    }
 }
@@ -0,0 +1,33 @@
 package com.ankurm.batch;
 import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.job.Job;
 import org.springframework.batch.core.job.JobExecution;
 import org.springframework.batch.core.job.parameters.JobParameters;
 import org.springframework.batch.core.job.parameters.JobParametersBuilder;
 import org.springframework.batch.core.launch.JobOperator;
 import org.springframework.batch.core.repository.JobRepository;
 import org.springframework.stereotype.Component;
@Component
 public class JobRunner {
    private final JobOperator operator;
    private final JobRepository repository;
    private final Job job;
    public JobRunner(JobOperator operator, JobRepository repository, Job squareJob) {
        this.operator = operator; this.repository = repository; this.job = squareJob;
    }
    public void run() {
        try {
            JobParameters params = new JobParametersBuilder().addLong("run.id", 1L).toJobParameters();
            JobExecution exec = operator.start(job, params);
            System.out.println("STATUS " + exec.getStatus() + " exit=" + exec.getExitStatus().getExitCode());
            System.out.println("INSTANCES " + repository.getJobInstanceCount("squareJob"));
            System.out.println("DONE " + (exec.getStatus() == BatchStatus.COMPLETED));
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }
 }
@@ -0,0 +1,3 @@
 spring.batch.job.enabled=false
 spring.datasource.url=jdbc:h2:mem:legacy;DB_CLOSE_DELAY=-1
 spring.batch.jdbc.initialize-schema=always
@@ -0,0 +1,23 @@
 package com.ankurm.batch;
 import static org.assertj.core.api.Assertions.assertThat;
 import org.junit.jupiter.api.Test;
 import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.job.JobExecution;
 import org.springframework.batch.test.JobOperatorTestUtils;
 import org.springframework.batch.test.context.SpringBatchTest;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
@SpringBatchTest
 class JobTest {
    @Autowired JobOperatorTestUtils utils;
    @Test
    void jobCompletes() throws Exception {
        JobExecution exec = utils.startJob();
        assertThat(exec.getStatus()).isEqualTo(BatchStatus.COMPLETED);
    }
 }
@@ -0,0 +1,15 @@
 $ mvn test   # Boot 3.5.16, Batch 5.2.6, JDK 21
 [INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 3.750 s -- in com.ankurm.batch.JobTest
 [INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
 [INFO] BUILD SUCCESS
 $ java -jar target/batch-legacy-1.0.0.jar
 WRITE [sq1, sq4, sq9]
 CHUNK DONE, read so far=3
 WRITE [sq16, sq25, sq36]
 CHUNK DONE, read so far=6
 WRITE [sq49]
 CHUNK DONE, read so far=7
 STATUS COMPLETED exit=COMPLETED
 INSTANCES 1
 DONE true
@@ -0,0 +1,10 @@
 $ mvn compile   # legacy sources, only the Boot version changed to 4.1.1 (Batch 6.0.5)
 compile error lines reported: 56
 packages that no longer exist:
 package org.springframework.batch.core.explore does not exist
 package org.springframework.batch.item does not exist
 package org.springframework.batch.item.support does not exist
 classes that moved:
 ChunkListener ItemReader ItemWriter Job JobExecution JobExplorer JobParameters JobParametersBuilder ListItemReader Step 
@@ -0,0 +1,19 @@
 $ mvn package   # imports ported to the new packages, dependencies unchanged (spring-boot-starter-batch)
 [WARNING] s2/src/main/java/com/ankurm/batch/BatchConfig.java:[34,35] afterChunk(org.springframework.batch.core.scope.context.ChunkContext) in org.springframework.batch.core.listener.ChunkListener has been deprecated and marked for removal
 [WARNING] s2/src/main/java/com/ankurm/batch/BatchConfig.java:[43,17] <I,O>chunk(int,org.springframework.transaction.PlatformTransactionManager) in org.springframework.batch.core.step.builder.StepBuilder has been deprecated and marked for removal
 [WARNING] s2/src/main/java/com/ankurm/batch/JobRunner.java:[14,19] org.springframework.batch.core.launch.JobLauncher in org.springframework.batch.core.launch has been deprecated and marked for removal
 [WARNING] s2/src/main/java/com/ankurm/batch/JobRunner.java:[15,19] org.springframework.batch.core.repository.explore.JobExplorer in org.springframework.batch.core.repository.explore has been deprecated and marked for removal
 [WARNING] s2/src/main/java/com/ankurm/batch/JobRunner.java:[18,22] org.springframework.batch.core.launch.JobLauncher in org.springframework.batch.core.launch has been deprecated and marked for removal
 [WARNING] s2/src/main/java/com/ankurm/batch/JobRunner.java:[18,44] org.springframework.batch.core.repository.explore.JobExplorer in org.springframework.batch.core.repository.explore has been deprecated and marked for removal
 [WARNING] s2/src/test/java/com/ankurm/batch/JobTest.java:[16,16] org.springframework.batch.test.JobLauncherTestUtils in org.springframework.batch.test has been deprecated and marked for removal
 [WARNING] s2/src/test/java/com/ankurm/batch/JobTest.java:[20,34] launchJob() in org.springframework.batch.test.JobLauncherTestUtils has been deprecated and marked for removal
 [INFO] BUILD SUCCESS
 $ java -jar target/batch-legacy-1.0.0.jar
 APPLICATION FAILED TO START
 ***************************
 Description:
 Parameter 1 of method squareStep in com.ankurm.batch.BatchConfig required a bean of type 'org.springframework.transaction.PlatformTransactionManager' that could not be found.
@@ -0,0 +1,23 @@
 $ mvn package   # + spring-boot-starter-batch-jdbc and spring-boot-starter-jdbc
 [WARNING] s3/src/main/java/com/ankurm/batch/BatchConfig.java:[34,35] afterChunk(org.springframework.batch.core.scope.context.ChunkContext) in org.springframework.batch.core.listener.ChunkListener has been deprecated and marked for removal
 [WARNING] s3/src/main/java/com/ankurm/batch/BatchConfig.java:[43,17] <I,O>chunk(int,org.springframework.transaction.PlatformTransactionManager) in org.springframework.batch.core.step.builder.StepBuilder has been deprecated and marked for removal
 [WARNING] s3/src/main/java/com/ankurm/batch/JobRunner.java:[14,19] org.springframework.batch.core.launch.JobLauncher in org.springframework.batch.core.launch has been deprecated and marked for removal
 [WARNING] s3/src/main/java/com/ankurm/batch/JobRunner.java:[15,19] org.springframework.batch.core.repository.explore.JobExplorer in org.springframework.batch.core.repository.explore has been deprecated and marked for removal
 [WARNING] s3/src/main/java/com/ankurm/batch/JobRunner.java:[18,22] org.springframework.batch.core.launch.JobLauncher in org.springframework.batch.core.launch has been deprecated and marked for removal
 [WARNING] s3/src/main/java/com/ankurm/batch/JobRunner.java:[18,44] org.springframework.batch.core.repository.explore.JobExplorer in org.springframework.batch.core.repository.explore has been deprecated and marked for removal
 [WARNING] s3/src/test/java/com/ankurm/batch/JobTest.java:[16,16] org.springframework.batch.test.JobLauncherTestUtils in org.springframework.batch.test has been deprecated and marked for removal
 [WARNING] s3/src/test/java/com/ankurm/batch/JobTest.java:[20,34] launchJob() in org.springframework.batch.test.JobLauncherTestUtils has been deprecated and marked for removal
 [INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 4.571 s -- in com.ankurm.batch.JobTest
 [INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
 [INFO] BUILD SUCCESS
 $ java -jar target/batch-legacy-1.0.0.jar
 WRITE [sq1, sq4, sq9]
 CHUNK DONE, read so far=3
 WRITE [sq16, sq25, sq36]
 CHUNK DONE, read so far=6
 WRITE [sq49]
 CHUNK DONE, read so far=7
 STATUS COMPLETED exit=COMPLETED
 INSTANCES 1
 DONE true
@@ -0,0 +1,17 @@
 $ mvn package   # chunk(3, tx) replaced by chunk(3).transactionManager(tx); listener untouched
 [WARNING] s4/src/main/java/com/ankurm/batch/BatchConfig.java:[34,35] afterChunk(org.springframework.batch.core.scope.context.ChunkContext) in org.springframework.batch.core.listener.ChunkListener has been deprecated and marked for removal
 [WARNING] s4/src/main/java/com/ankurm/batch/JobRunner.java:[14,19] org.springframework.batch.core.launch.JobLauncher in org.springframework.batch.core.launch has been deprecated and marked for removal
 [WARNING] s4/src/main/java/com/ankurm/batch/JobRunner.java:[15,19] org.springframework.batch.core.repository.explore.JobExplorer in org.springframework.batch.core.repository.explore has been deprecated and marked for removal
 [WARNING] s4/src/main/java/com/ankurm/batch/JobRunner.java:[18,22] org.springframework.batch.core.launch.JobLauncher in org.springframework.batch.core.launch has been deprecated and marked for removal
 [WARNING] s4/src/main/java/com/ankurm/batch/JobRunner.java:[18,44] org.springframework.batch.core.repository.explore.JobExplorer in org.springframework.batch.core.repository.explore has been deprecated and marked for removal
 [WARNING] s4/src/test/java/com/ankurm/batch/JobTest.java:[16,16] org.springframework.batch.test.JobLauncherTestUtils in org.springframework.batch.test has been deprecated and marked for removal
 [WARNING] s4/src/test/java/com/ankurm/batch/JobTest.java:[20,34] launchJob() in org.springframework.batch.test.JobLauncherTestUtils has been deprecated and marked for removal
 [INFO] BUILD SUCCESS
 $ java -jar target/batch-legacy-1.0.0.jar
 WRITE [sq1, sq4, sq9]
 WRITE [sq16, sq25, sq36]
 WRITE [sq49]
 STATUS COMPLETED exit=COMPLETED
 INSTANCES 1
 DONE true
@@ -0,0 +1,15 @@
 $ mvn package   # final migrated project
 [INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 4.029 s -- in com.ankurm.batch.JobTest
 [INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
 [INFO] BUILD SUCCESS
 $ java -jar target/batch-migrated-1.0.0.jar
 WRITE [sq1, sq4, sq9]
 CHUNK DONE, items in chunk=3
 WRITE [sq16, sq25, sq36]
 CHUNK DONE, items in chunk=3
 WRITE [sq49]
 CHUNK DONE, items in chunk=1
 STATUS COMPLETED exit=COMPLETED
 INSTANCES 1
 DONE true
@@ -0,0 +1,13 @@
 $ javap (Batch 6.0.5 jars), selected lines
 public interface core.launch.JobOperator extends core.launch.JobLauncher {
 public interface core.repository.JobRepository extends core.repository.explore.JobExplorer {
 public class test.JobOperatorTestUtils extends test.JobLauncherTestUtils {
  public <I, O> core.step.builder.SimpleStepBuilder<I, O> chunk(int, PlatformTransactionManager);
  public <I, O> core.step.builder.ChunkOrientedStepBuilder<I, O> chunk(int);
  public <I, O> core.step.builder.SimpleStepBuilder<I, O> chunk(infrastructure.repeat.CompletionPolicy, PlatformTransactionManager);
  public default void beforeChunk(core.scope.context.ChunkContext);
  public default void afterChunk(core.scope.context.ChunkContext);
  public default void afterChunkError(core.scope.context.ChunkContext);
  public default void beforeChunk(infrastructure.item.Chunk<I>);
  public default void afterChunk(infrastructure.item.Chunk<O>);
  public default void onChunkError(java.lang.Exception, infrastructure.item.Chunk<O>);
@@ -0,0 +1,69 @@
 #!/usr/bin/env bash
 # Regenerates output/*.txt. Needs Maven, JDK 21 (J21) and JDK 25 (J25); network for Maven Central.
 set -u
 HERE=$(cd "$(dirname "$0")/.." && pwd); OUT=$HERE/output; W=${WORK:-/tmp/b56-work}
 J21=${J21:-/usr/lib/jvm/java-21-openjdk-amd64}; J25=${J25:-/tmp/tools/jdk-25.0.4.1+1}; MVN=${MVN:-mvn}
 mkdir -p "$OUT"; rm -rf "$W"; mkdir -p "$W"
 mv_() { local jh=$1 d=$2; shift 2; (cd "$d" && JAVA_HOME=$jh $MVN -B -Dmaven.compiler.showDeprecation=true "$@" 2>&1 | grep -v JAVA_TOOL_OPTIONS | sed "s#$W/##g"); }
 runjar() { local jh=$1 jar=$2; JAVA_HOME=$jh $jh/bin/java -jar "$jar" 2>&1 | grep -E '^(WRITE|CHUNK|STATUS|INSTANCES|DONE)'; }
 stage() { rm -rf "$W/$1"; cp -r "$HERE/$2" "$W/$1"; rm -rf "$W/$1/target"; }
 PORT_IMPORTS=$(cat <<'PY'
 import glob,sys
 m={'org.springframework.batch.core.ChunkListener':'org.springframework.batch.core.listener.ChunkListener',
 'org.springframework.batch.core.Job;':'org.springframework.batch.core.job.Job;',
 'org.springframework.batch.core.Step;':'org.springframework.batch.core.step.Step;',
 'org.springframework.batch.core.JobExecution;':'org.springframework.batch.core.job.JobExecution;',
 'org.springframework.batch.core.JobParameters;':'org.springframework.batch.core.job.parameters.JobParameters;',
 'org.springframework.batch.core.JobParametersBuilder':'org.springframework.batch.core.job.parameters.JobParametersBuilder',
 'org.springframework.batch.core.explore.JobExplorer':'org.springframework.batch.core.repository.explore.JobExplorer',
 'org.springframework.batch.item.':'org.springframework.batch.infrastructure.item.'}
 for f in glob.glob(sys.argv[1]+'/src/**/*.java',recursive=True):
    s=open(f).read()
    for a,b in m.items(): s=s.replace(a,b)
    open(f,'w').write(s)
 PY
 )
 # 01 legacy: Boot 3.5.16 / Batch 5.2.6
 stage s0 legacy
 { echo '$ mvn test   # Boot 3.5.16, Batch 5.2.6, JDK 21'; mv_ "$J21" "$W/s0" package | grep -E 'Tests run:|BUILD'
  echo; echo '$ java -jar target/batch-legacy-1.0.0.jar'; runjar "$J21" "$W/s0/target/batch-legacy-1.0.0.jar"; } > "$OUT/01-legacy-batch5.txt"
 # 02 same sources, Boot 4.1.1
 stage s1 legacy; sed -i 's/3.5.16/4.1.1/; s/<java.version>21/<java.version>25/' "$W/s1/pom.xml"
 { echo '$ mvn compile   # legacy sources, only the Boot version changed to 4.1.1 (Batch 6.0.5)'
  mv_ "$J25" "$W/s1" compile > "$W/s1.log"
  echo "compile error lines reported: $(grep -c '^\[ERROR\] .*\.java' "$W/s1.log")"; echo; echo 'packages that no longer exist:'
  grep -oE 'package [a-z.]+ does not exist' "$W/s1.log" | sort -u; echo; echo 'classes that moved:'
  grep -oE 'symbol: +class [A-Za-z]+' "$W/s1.log" | awk '{print $3}' | sort -u | tr '\n' ' '; echo; } > "$OUT/02-compile-errors-after-bump.txt"
 # 03 imports ported, dependencies untouched
 cp -r "$W/s1" "$W/s2"; rm -rf "$W/s2/target"; python3 -c "$PORT_IMPORTS" "$W/s2"
 { echo '$ mvn package   # imports ported to the new packages, dependencies unchanged (spring-boot-starter-batch)'
  mv_ "$J25" "$W/s2" -DskipTests package | grep -E 'WARNING.*\.java|BUILD|ERROR.*\.java'
  echo; echo '$ java -jar target/batch-legacy-1.0.0.jar'
  JAVA_HOME=$J25 $J25/bin/java -jar "$W/s2/target/batch-legacy-1.0.0.jar" 2>&1 | grep -A6 'APPLICATION FAILED'; } > "$OUT/03-imports-ported-no-transaction-manager.txt"
 # 04 + JDBC starter
 cp -r "$W/s2" "$W/s3"; rm -rf "$W/s3/target"; python3 - "$W/s3/pom.xml" <<'PY'
 import sys; p=sys.argv[1]; s=open(p).read()
 s=s.replace('<artifactId>spring-boot-starter-batch</artifactId></dependency>','<artifactId>spring-boot-starter-batch-jdbc</artifactId></dependency>\n    <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency>')
 open(p,'w').write(s)
 PY
 { echo '$ mvn package   # + spring-boot-starter-batch-jdbc and spring-boot-starter-jdbc'
  mv_ "$J25" "$W/s3" package | grep -E 'WARNING.*\.java|Tests run:|BUILD'
  echo; echo '$ java -jar target/batch-legacy-1.0.0.jar'; runjar "$J25" "$W/s3/target/batch-legacy-1.0.0.jar"; } > "$OUT/04-jdbc-starter-added.txt"
 # 05 new chunk API but old listener
 cp -r "$W/s3" "$W/s4"; rm -rf "$W/s4/target"; sed -i 's/\.<Integer, String>chunk(3, tx)/.<Integer, String>chunk(3)\n                .transactionManager(tx)/' "$W/s4/src/main/java/com/ankurm/batch/BatchConfig.java"
 { echo '$ mvn package   # chunk(3, tx) replaced by chunk(3).transactionManager(tx); listener untouched'
  mv_ "$J25" "$W/s4" -DskipTests package | grep -E 'WARNING.*\.java|BUILD|ERROR.*\.java'
  echo; echo '$ java -jar target/batch-legacy-1.0.0.jar'; runjar "$J25" "$W/s4/target/batch-legacy-1.0.0.jar"; } > "$OUT/05-new-chunk-api-listener-silent.txt"
 # 06 final migrated
 stage m migrated
 { echo '$ mvn package   # final migrated project'
  mv_ "$J25" "$W/m" package | grep -E 'WARNING.*\.java|Tests run:|BUILD'
  echo; echo '$ java -jar target/batch-migrated-1.0.0.jar'; runjar "$J25" "$W/m/target/batch-migrated-1.0.0.jar"; } > "$OUT/06-migrated.txt"
 # 07 API facts from the jars
 M2=${M2:-$HOME/.m2/repository/org/springframework/batch}
 CP=$M2/spring-batch-core/6.0.5/spring-batch-core-6.0.5.jar:$M2/spring-batch-infrastructure/6.0.5/spring-batch-infrastructure-6.0.5.jar:$M2/spring-batch-test/6.0.5/spring-batch-test-6.0.5.jar
 { echo '$ javap (Batch 6.0.5 jars), selected lines'
  for c in org.springframework.batch.core.launch.JobOperator org.springframework.batch.core.repository.JobRepository org.springframework.batch.test.JobOperatorTestUtils; do env -u JAVA_TOOL_OPTIONS $J25/bin/javap -cp $CP $c 2>&1 | grep -E '^public (interface|class)' | sed 's/org\.springframework\.batch\.//g'; done
  env -u JAVA_TOOL_OPTIONS $J25/bin/javap -cp $CP org.springframework.batch.core.step.builder.StepBuilder 2>&1 | grep -E ' chunk\(' | sed 's/org\.springframework\.batch\.//g; s/org\.springframework\.transaction\.//g; s/org\.springframework\.//g'
  env -u JAVA_TOOL_OPTIONS $J25/bin/javap -cp $CP org.springframework.batch.core.listener.ChunkListener 2>&1 | grep -E 'Chunk(Context|<)' | sed 's/org\.springframework\.batch\.//g'; } > "$OUT/07-api-facts.txt"
 echo done
@@ -0,0 +1,16 @@
 # boot42-preview
 Companion module for the ankurm.com article *Spring Boot 4.2 Preview: AMQP 1.0, Buildpack Image Cache and What to Test Now*.
 Everything runs against **4.2.0-M2** (a milestone, not GA) and, where a comparison matters, against **4.1.1** (GA).
 | Path | What it is |
 |---|---|
 | `pom.xml` / `pom-41.xml` | the same project on 4.2.0-M2 and on 4.1.1 (a `${revision}` parent does not resolve from a repository, hence two files) |
 | `src/test/.../ForwardedHeadersTest` | what the container believes under each forwarded-header strategy |
 | `src/test/.../BindingOrderTest` | Set and Map iteration order from a properties file |
 | `src/broken/UsesRestTemplate.java` | not built; compiled by the facts script to capture the deprecation warnings |
 | `src/main/.../RestClientReplacement` | the replacement, compiled clean |
 | `examples/build-image-cache-fragment.xml` | **not executed** (needs Docker and a registry) |
 | `output/` | every transcript quoted in the article; `./scripts/run-all.sh` regenerates them |
 There is deliberately no `docs/` folder: the explanations live in the article.
@@ -0,0 +1,15 @@
 <!-- NOT EXECUTED: needs a Docker daemon and a registry. Element names come from the setters javap shows in
     output/04-buildpack-cache-classes.txt (CacheInfo.setImage, ImageCacheInfo.setName). -->
 <plugin>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-maven-plugin</artifactId>
  <configuration>
    <image>
      <buildCache>
        <image>
          <name>registry.example.com/team/demo-build-cache:latest</name>
        </image>
      </buildCache>
    </image>
  </configuration>
 </plugin>
@@ -0,0 +1,10 @@
 # 01-forwarded-headers  (Spring Boot 4.1.1, JDK 25)
 none/x-forwarded       scheme=http secure=false host=localhost port=<random>
 none/rfc7239           scheme=http secure=false host=localhost port=<random>
 native/x-forwarded     scheme=https secure=true host=shop.example.com port=443
 native/rfc7239         scheme=http secure=false host=localhost port=<random>
 framework/x-forwarded  scheme=https secure=true host=shop.example.com port=443
 framework/rfc7239      scheme=https secure=true host=shop.example.com port=443
 framework+standard/x-forwarded scheme=https secure=true host=shop.example.com port=443
 framework+standard/rfc7239 scheme=https secure=true host=shop.example.com port=443
 header-format=forwarded -> started (property ignored)
@@ -0,0 +1,10 @@
 # 01-forwarded-headers  (Spring Boot 4.2.0-M2, JDK 25)
 none/x-forwarded       scheme=http secure=false host=localhost port=<random>
 none/rfc7239           scheme=http secure=false host=localhost port=<random>
 native/x-forwarded     scheme=https secure=true host=shop.example.com port=443
 native/rfc7239         scheme=http secure=false host=localhost port=<random>
 framework/x-forwarded  scheme=https secure=true host=shop.example.com port=443
 framework/rfc7239      scheme=http secure=false host=localhost port=<random>
 framework+standard/x-forwarded scheme=http secure=false host=localhost port=<random>
 framework+standard/rfc7239 scheme=https secure=true host=shop.example.com port=443
 header-format=forwarded -> IllegalArgumentException: No enum constant org.springframework.boot.webmvc.autoconfigure.WebMvcProperties.HeaderFormat.forwarded
@@ -0,0 +1,6 @@
 # 02-set-and-map-binding-order  (Spring Boot 4.1.1, JDK 25)
 file order    : zulu, alpha, mike, bravo, yankee, charlie
 Set class     : java.util.LinkedHashSet
 Set order     : [zulu, alpha, mike, bravo, yankee, charlie]
 Map class     : java.util.LinkedHashMap
 Map key order : [zulu, alpha, mike, bravo, yankee, charlie]
@@ -0,0 +1,6 @@
 # 02-set-and-map-binding-order  (Spring Boot 4.2.0-M2, JDK 25)
 file order    : zulu, alpha, mike, bravo, yankee, charlie
 Set class     : java.util.LinkedHashSet
 Set order     : [zulu, alpha, mike, bravo, yankee, charlie]
 Map class     : java.util.LinkedHashMap
 Map key order : [zulu, alpha, mike, bravo, yankee, charlie]
@@ -0,0 +1,24 @@
 # 03-amqp-starters (POM descriptions and contents straight from Maven Central)
 spring-boot-starter-amqp           4.1.1      HTTP 200  "Starter for using Spring AMQP and Rabbit MQ"  -> spring-boot-amqp
 spring-boot-starter-amqp           4.2.0-M2   HTTP 200  "Starter for generic AMQP 1.0 support"  -> spring-boot-amqp
 spring-boot-starter-rabbitmq       4.1.1      HTTP 404  (does not exist)
 spring-boot-starter-rabbitmq       4.2.0-M2   HTTP 200  "Starter for using RabbitMQ messaging and streaming broker"  -> spring-boot-rabbitmq
 spring-boot-starter-amqp-rabbitmq  4.1.1      HTTP 404  (does not exist)
 spring-boot-starter-amqp-rabbitmq  4.2.0-M2   HTTP 200  "Starter for using Spring AMQP with Rabbit MQ over AMQP 1.0 protocol"  -> spring-boot-amqp-rabbitmq
 # auto-configuration each module registers (AutoConfiguration.imports)
 --- spring-boot-amqp 4.1.1
  org.springframework.boot.amqp.autoconfigure.RabbitAutoConfiguration
  org.springframework.boot.amqp.autoconfigure.health.RabbitHealthContributorAutoConfiguration
  org.springframework.boot.amqp.autoconfigure.metrics.RabbitMetricsAutoConfiguration
 --- spring-boot-amqp 4.2.0-M2
  org.springframework.boot.amqp.autoconfigure.AmqpAutoConfiguration
 --- spring-boot-rabbitmq 4.2.0-M2
  org.springframework.boot.rabbitmq.autoconfigure.RabbitAutoConfiguration
  org.springframework.boot.rabbitmq.autoconfigure.health.RabbitHealthContributorAutoConfiguration
  org.springframework.boot.rabbitmq.autoconfigure.metrics.RabbitMetricsAutoConfiguration
 --- spring-boot-amqp-rabbitmq 4.2.0-M2
  org.springframework.boot.amqp.rabbitmq.autoconfigure.AmqpRabbitAutoConfiguration
  org.springframework.boot.amqp.rabbitmq.autoconfigure.health.AmqpRabbitHealthContributorAutoConfiguration
@@ -0,0 +1,50 @@
 # 04-buildpack-cache-classes (javap, spring-boot-buildpack-platform and spring-boot-maven-plugin)
 --- buildpack-platform 4.1.1: classes matching Cache
  Cache$Bind.class
  Cache$Format.class
  Cache$Volume.class
  Cache.class
 --- buildpack-platform 4.2.0-M2: classes matching Cache
  Cache.class
  ImageCache.class
  LocalCache$Bind.class
  LocalCache$Volume.class
  LocalCache.class
 --- javap Cache (4.2.0-M2)
 Compiled from "Cache.java"
 public interface Cache {
  public default LocalCache$Volume getVolume();
  public default LocalCache$Bind getBind();
  public default ImageCache getImage();
  public static LocalCache volume(java.lang.String);
  public static LocalCache volume(VolumeName);
  public static LocalCache bind(java.lang.String);
  public static ImageCache image(java.lang.String);
 }
 --- javap org.springframework.boot.maven.CacheInfo (4.2.0-M2)
 Compiled from "CacheInfo.java"
 public class CacheInfo {
  public CacheInfo();
  public void setVolume(LocalCacheInfo$VolumeCacheInfo);
  public void setBind(LocalCacheInfo$BindCacheInfo);
  public void setImage(CacheInfo$ImageCacheInfo);
  Cache asCache();
  static CacheInfo fromVolume(LocalCacheInfo$VolumeCacheInfo);
  static CacheInfo fromBind(LocalCacheInfo$BindCacheInfo);
  static CacheInfo fromImage(CacheInfo$ImageCacheInfo);
 }
 --- javap org.springframework.boot.maven.LocalCacheInfo (4.2.0-M2)
 Compiled from "LocalCacheInfo.java"
 public class LocalCacheInfo {
  public LocalCacheInfo();
  LocalCacheInfo(LocalCache);
  public void setVolume(LocalCacheInfo$VolumeCacheInfo);
  public void setBind(LocalCacheInfo$BindCacheInfo);
  LocalCache asCache();
  static LocalCacheInfo fromVolume(LocalCacheInfo$VolumeCacheInfo);
  static LocalCacheInfo fromBind(LocalCacheInfo$BindCacheInfo);
 }
 --- javap -p Image, fields mentioning cache/workspace (4.2.0-M2)
  LocalCacheInfo buildWorkspace;
  CacheInfo buildCache;
  LocalCacheInfo launchCache;
@@ -0,0 +1,22 @@
 # 05-resttemplate-deprecations (javac -Xlint:deprecation on src/broken/UsesRestTemplate.java)
 --- Spring Boot 4.1.1
 --- Spring Boot 4.2.0-M2
 UsesRestTemplate.java:8: warning: [removal] RestTemplate in org.springframework.web.client has been deprecated and marked for removal
 	RestTemplate viaBuilder(RestTemplateBuilder builder) {
 	^
 UsesRestTemplate.java:8: warning: [removal] RestTemplateBuilder in org.springframework.boot.restclient has been deprecated and marked for removal
 	RestTemplate viaBuilder(RestTemplateBuilder builder) {
 	                        ^
 UsesRestTemplate.java:12: warning: [removal] TestRestTemplate in org.springframework.boot.resttestclient has been deprecated and marked for removal
 	TestRestTemplate viaTest(TestRestTemplate t) {
 	^
 UsesRestTemplate.java:12: warning: [removal] TestRestTemplate in org.springframework.boot.resttestclient has been deprecated and marked for removal
 	TestRestTemplate viaTest(TestRestTemplate t) {
 	                         ^
 UsesRestTemplate.java:16: warning: [removal] RestTemplate in org.springframework.web.client has been deprecated and marked for removal
 	RestTemplate plain() {
 	^
 UsesRestTemplate.java:17: warning: [removal] RestTemplate in org.springframework.web.client has been deprecated and marked for removal
 		return new RestTemplate();
 		           ^
 6 warnings
@@ -0,0 +1,2 @@
 # 06-restclient-replacement (javac -Xlint:deprecation on the RestClient version, Spring Boot 4.2.0-M2)
 javac finished; lines above this one are warnings (none means a clean compile)
@@ -0,0 +1,57 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>4.1.1</version>
    <relativePath/>
  </parent>
  <groupId>com.ankurm</groupId>
  <artifactId>boot42-preview-on-41</artifactId>
  <version>1.0.0</version>
  <name>boot42-preview</name>
  <description>Spring Boot 4.2 milestone preview: what to test now, run against 4.2.0-M2 and 4.1.1</description>
  <properties>
    <java.version>25</java.version>
    <boot.label>4.1.1</boot.label>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-webmvc</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-restclient</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-webmvc-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-surefire-plugin</artifactId>
        <configuration>
          <systemPropertyVariables>
            <boot.label>${boot.label}</boot.label>
          </systemPropertyVariables>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
 </project>
@@ -0,0 +1,57 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>4.2.0-M2</version>
    <relativePath/>
  </parent>
  <groupId>com.ankurm</groupId>
  <artifactId>boot42-preview</artifactId>
  <version>1.0.0</version>
  <name>boot42-preview</name>
  <description>Spring Boot 4.2 milestone preview: what to test now, run against 4.2.0-M2 and 4.1.1</description>
  <properties>
    <java.version>25</java.version>
    <boot.label>4.2.0-M2</boot.label>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-webmvc</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-restclient</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-webmvc-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-surefire-plugin</artifactId>
        <configuration>
          <systemPropertyVariables>
            <boot.label>${boot.label}</boot.label>
          </systemPropertyVariables>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
 </project>
@@ -0,0 +1,78 @@
 #!/usr/bin/env bash
 # Facts read from jars and POMs on Maven Central: nothing here needs a running application.
 set -euo pipefail
 cd "$(dirname "$0")/.."
 M="$HOME/.m2/repository/org/springframework/boot"
 CEN=https://repo1.maven.org/maven2/org/springframework/boot
 W=$(mktemp -d)
 for v in 4.1.1 4.2.0-M2; do for a in spring-boot-maven-plugin spring-boot-buildpack-platform spring-boot-amqp spring-boot-amqp-rabbitmq spring-boot-rabbitmq; do
  mvn -B -q dependency:get -Dartifact=org.springframework.boot:$a:$v >/dev/null 2>&1 || true
 done; done
 {
  echo "# 03-amqp-starters (POM descriptions and contents straight from Maven Central)"
  for a in spring-boot-starter-amqp spring-boot-starter-rabbitmq spring-boot-starter-amqp-rabbitmq; do
    for v in 4.1.1 4.2.0-M2; do
      for try in 1 2 3 4 5; do
        code=$(curl -s -o "$W/p.xml" -w '%{http_code}' "$CEN/$a/$v/$a-$v.pom")
        [ "$code" = 429 ] || break
        sleep $((try * 3))
      done
      if [ "$code" = 200 ]; then
        d=$(grep -m1 '<description>' "$W/p.xml" | sed 's/ *<[^>]*>//g')
        dep=$(grep -E '<artifactId>spring-boot-(amqp|rabbitmq|amqp-rabbitmq)</artifactId>' "$W/p.xml" | sed 's/ *<[^>]*>//g' | paste -sd, -)
        printf '%-34s %-10s HTTP %s  "%s"  -> %s\n' "$a" "$v" "$code" "$d" "$dep"
      else
        printf '%-34s %-10s HTTP %s  (does not exist)\n' "$a" "$v" "$code"
      fi
    done
  done
  echo
  echo "# auto-configuration each module registers (AutoConfiguration.imports)"
  for a in spring-boot-amqp spring-boot-rabbitmq spring-boot-amqp-rabbitmq; do
    for v in 4.1.1 4.2.0-M2; do
      j="$M/$a/$v/$a-$v.jar"
      if [ -f "$j" ]; then
        echo "--- $a $v"; unzip -p "$j" META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports 2>/dev/null | sed 's/^/  /' || true; echo
      fi
    done
  done
 } > output/03-amqp-starters.txt
 {
  echo "# 04-buildpack-cache-classes (javap, spring-boot-buildpack-platform and spring-boot-maven-plugin)"
  for v in 4.1.1 4.2.0-M2; do
    echo "--- buildpack-platform $v: classes matching Cache"
    unzip -l "$M/spring-boot-buildpack-platform/$v/spring-boot-buildpack-platform-$v.jar" | awk '{print $4}' | grep -E 'build/.*Cache' | sed 's#.*/build/#  #'
  done
  mkdir -p "$W/bp"
  unzip -q -o "$M/spring-boot-buildpack-platform/4.2.0-M2/spring-boot-buildpack-platform-4.2.0-M2.jar" 'org/springframework/boot/buildpack/platform/build/*Cache*' -d "$W/bp"
  unzip -q -o "$M/spring-boot-maven-plugin/4.2.0-M2/spring-boot-maven-plugin-4.2.0-M2.jar" 'org/springframework/boot/maven/*' -d "$W/bp"
  echo "--- javap Cache (4.2.0-M2)"
  javap -cp "$W/bp" org.springframework.boot.buildpack.platform.build.Cache 2>/dev/null | sed 's/org.springframework.boot.buildpack.platform.build.//g; s/org.springframework.boot.buildpack.platform.docker.type.//g'
  for c in 'org.springframework.boot.maven.CacheInfo' 'org.springframework.boot.maven.LocalCacheInfo'; do
    echo "--- javap $c (4.2.0-M2)"
    javap -cp "$W/bp" "$c" 2>/dev/null | sed 's/org.springframework.boot.maven.//g; s/org.springframework.boot.buildpack.platform.build.//g'
  done
  echo "--- javap -p Image, fields mentioning cache/workspace (4.2.0-M2)"
  javap -p -cp "$W/bp" org.springframework.boot.maven.Image 2>/dev/null | grep -E '(Cache|buildWorkspace)[a-zA-Z]* [a-zA-Z]+;$' | sed 's/org.springframework.boot.maven.//g'
 } > output/04-buildpack-cache-classes.txt
 {
  echo "# 05-resttemplate-deprecations (javac -Xlint:deprecation on src/broken/UsesRestTemplate.java)"
  for pom in pom-41.xml pom.xml; do
    mvn -B -q -f $pom dependency:build-classpath -Dmdep.outputFile="$W/cp.txt" >/dev/null 2>&1
    label=$([ $pom = pom.xml ] && echo 4.2.0-M2 || echo 4.1.1)
    echo "--- Spring Boot $label"
    mkdir -p "$W/out-$label"
    javac -Xlint:deprecation -d "$W/out-$label" -cp "$(cat "$W/cp.txt")" src/broken/UsesRestTemplate.java 2>&1 | grep -v JAVA_TOOL | sed 's#^src/broken/##' || true
  done
 } > output/05-resttemplate-deprecations.txt
 {
  echo "# 06-restclient-replacement (javac -Xlint:deprecation on the RestClient version, Spring Boot 4.2.0-M2)"
  mvn -B -q dependency:build-classpath -Dmdep.outputFile="$W/cp.txt" >/dev/null 2>&1
  mkdir -p "$W/out-rc"
  javac -Xlint:deprecation -Xlint:removal -d "$W/out-rc" -cp "$(cat "$W/cp.txt")" src/main/java/com/ankurm/boot42/RestClientReplacement.java 2>&1 | grep -v JAVA_TOOL | sed 's#^src/main/java/com/ankurm/boot42/##' || true
  echo "javac finished; lines above this one are warnings (none means a clean compile)"
 } > output/06-restclient-replacement.txt
@@ -0,0 +1,11 @@
 #!/usr/bin/env bash
 # Regenerates every file under output/. Needs JDK 25 and Maven 3.9 with network access to Maven Central.
 #   ./scripts/run-all.sh
 # 01-02 come from the test suite (run on 4.2.0-M2, then on 4.1.1 via pom-41.xml, which writes the *-on-4.1.1 files).
 # 03-06 come from jars, POMs and javac. Port numbers are random, so the transcripts print "<random>".
 set -euo pipefail
 cd "$(dirname "$0")/.."
 mvn -B test
 mvn -B -f pom-41.xml test
 ./scripts/capture-facts.sh
 ls -1 output
@@ -0,0 +1,19 @@
 import org.springframework.boot.restclient.RestTemplateBuilder;
 import org.springframework.boot.resttestclient.TestRestTemplate;
 import org.springframework.web.client.RestTemplate;
 /** Not part of the build: compiled by scripts/capture-facts.sh so the compiler's own words are committed. */
 class UsesRestTemplate {
 	RestTemplate viaBuilder(RestTemplateBuilder builder) {
 		return builder.build();
 	}
 	TestRestTemplate viaTest(TestRestTemplate t) {
 		return t;
 	}
 	RestTemplate plain() {
 		return new RestTemplate();
 	}
 }
@@ -0,0 +1,9 @@
 package com.ankurm.boot42;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 /** Minimal application. Every experiment in this module lives in src/test. */
@SpringBootApplication
@org.springframework.boot.context.properties.EnableConfigurationProperties(OrderProperties.class)
 public class Boot42PreviewApplication {
 }
@@ -0,0 +1,10 @@
 package com.ankurm.boot42;
 import java.util.Map;
 import java.util.Set;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 /** A Set and a Map bound from a file where the keys are deliberately not alphabetical. */
@ConfigurationProperties("app")
 public record OrderProperties(Set<String> regions, Map<String, Integer> limits) {
 }
@@ -0,0 +1,15 @@
 package com.ankurm.boot42;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.client.RestClient;
 /** What the deprecated RestTemplateBuilder code turns into: an injected RestClient.Builder. */
@Configuration(proxyBeanMethods = false)
 class RestClientReplacement {
 	@Bean
 	RestClient inventoryClient(RestClient.Builder builder) {
 		return builder.baseUrl("http://inventory.internal").build();
 	}
 }
@@ -0,0 +1,23 @@
 package com.ankurm.boot42;
 import jakarta.servlet.http.HttpServletRequest;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 /** Echoes what the servlet container believes about the request, after any forwarded-header handling. */
@RestController
 class WhoAmIController {
 	@GetMapping("/whoami")
 	Map<String, Object> whoAmI(HttpServletRequest request) {
 		Map<String, Object> m = new LinkedHashMap<>();
 		m.put("scheme", request.getScheme());
 		m.put("secure", request.isSecure());
 		m.put("serverName", request.getServerName());
 		m.put("serverPort", request.getServerPort());
 		m.put("remoteAddr", request.getRemoteAddr());
 		return m;
 	}
 }
@@ -0,0 +1,7 @@
 app.regions=zulu,alpha,mike,bravo,yankee,charlie
 app.limits.zulu=1
 app.limits.alpha=2
 app.limits.mike=3
 app.limits.bravo=4
 app.limits.yankee=5
 app.limits.charlie=6
@@ -0,0 +1,26 @@
 package com.ankurm.boot42;
 import static org.assertj.core.api.Assertions.assertThat;
 import java.util.ArrayList;
 import org.junit.jupiter.api.Test;
 import org.springframework.context.ConfigurableApplicationContext;
 /** 4.2.0-M1: Sets and Maps bind consistently and keep the order of the configuration file. */
 class BindingOrderTest {
 	@Test
 	void recordsIterationOrder() {
 		Transcript t = new Transcript("02-set-and-map-binding-order");
 		try (ConfigurableApplicationContext ctx = BootRun.start("spring.config.name=order")) {
 			OrderProperties p = ctx.getBean(OrderProperties.class);
 			t.line("file order    : zulu, alpha, mike, bravo, yankee, charlie");
 			t.line("Set class     : " + p.regions().getClass().getName());
 			t.line("Set order     : " + new ArrayList<>(p.regions()));
 			t.line("Map class     : " + p.limits().getClass().getName());
 			t.line("Map key order : " + new ArrayList<>(p.limits().keySet()));
 			t.write();
 			assertThat(p.regions()).hasSize(6);
 		}
 	}
 }
@@ -0,0 +1,32 @@
 package com.ankurm.boot42;
 import java.util.Map;
 import org.springframework.boot.WebApplicationType;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.env.Environment;
 import org.springframework.web.client.RestClient;
 /** Starts the real application with the given properties on a random port. */
 final class BootRun {
 	private BootRun() {
 	}
 	static ConfigurableApplicationContext start(String... props) {
 		return new SpringApplicationBuilder(Boot42PreviewApplication.class)
 				.web(WebApplicationType.SERVLET)
 				.properties(props)
 				.properties("server.port=0", "spring.main.banner-mode=off", "logging.level.root=WARN")
 				.run();
 	}
 	static RestClient client(ConfigurableApplicationContext ctx) {
 		Environment env = ctx.getEnvironment();
 		return RestClient.create("http://localhost:" + env.getProperty("local.server.port"));
 	}
 	static Map<?, ?> whoAmI(ConfigurableApplicationContext ctx, Map<String, String> headers) {
 		return client(ctx).get().uri("/whoami").headers(h -> headers.forEach(h::add)).retrieve().body(Map.class);
 	}
 }
@@ -0,0 +1,67 @@
 package com.ankurm.boot42;
 import static org.assertj.core.api.Assertions.assertThat;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 import org.springframework.context.ConfigurableApplicationContext;
 /**
 * 4.2.0-M1: "When server.forward-headers-strategy=FRAMEWORK is selected, X-Forwarded-* headers are used by
 * default." Sends both header styles under each strategy and records what the container believes.
 */
 class ForwardedHeadersTest {
 	private static final Map<String, String> X_FORWARDED = Map.of("X-Forwarded-Proto", "https",
 			"X-Forwarded-Host", "shop.example.com", "X-Forwarded-Port", "443");
 	private static final Map<String, String> RFC_7239 = Map.of("Forwarded", "proto=https;host=shop.example.com");
 	private static final Map<String, Map<String, String>> HEADERS = new LinkedHashMap<>();
 	static {
 		HEADERS.put("x-forwarded", X_FORWARDED);
 		HEADERS.put("rfc7239", RFC_7239);
 	}
 	@Test
 	void recordsBehaviourPerStrategy() {
 		Transcript t = new Transcript("01-forwarded-headers");
 		Map<String, Map<?, ?>> results = new LinkedHashMap<>();
 		for (String strategy : new String[] { "none", "native", "framework" }) {
 			for (var e : HEADERS.entrySet()) {
 				try (ConfigurableApplicationContext ctx = BootRun.start("server.forward-headers-strategy=" + strategy)) {
 					Map<?, ?> seen = BootRun.whoAmI(ctx, e.getValue());
 					String key = strategy + "/" + e.getKey();
 					results.put(key, seen);
 					t.line(String.format("%-22s scheme=%s secure=%s host=%s port=%s", key, seen.get("scheme"),
 							seen.get("secure"), seen.get("serverName"), seen.get("serverPort").toString().equals("443") ? "443" : "<random>"));
 				}
 			}
 		}
 		// the new 4.2 knob: which header family the FRAMEWORK strategy reads
 		for (var e : HEADERS.entrySet()) {
 			try (ConfigurableApplicationContext ctx = BootRun.start("server.forward-headers-strategy=framework",
 					"spring.mvc.forwarded-headers.header-format=standard")) {
 				Map<?, ?> seen = BootRun.whoAmI(ctx, e.getValue());
 				t.line(String.format("%-22s scheme=%s secure=%s host=%s port=%s", "framework+standard/" + e.getKey(),
 						seen.get("scheme"), seen.get("secure"), seen.get("serverName"), seen.get("serverPort").toString().equals("443") ? "443" : "<random>"));
 			}
 		}
 		// my first guess at the value was "forwarded"; record what the binder says about it
 		try (ConfigurableApplicationContext ctx = BootRun.start("server.forward-headers-strategy=framework",
 				"spring.mvc.forwarded-headers.header-format=forwarded")) {
 			t.line("header-format=forwarded -> started (property ignored)");
 		}
 		catch (Exception ex) {
 			Throwable root = ex;
 			while (root.getCause() != null) {
 				root = root.getCause();
 			}
 			t.line("header-format=forwarded -> " + root.getClass().getSimpleName() + ": " + root.getMessage());
 		}
 		t.write();
 		// a strategy of "none" must never trust either header
 		assertThat(results.get("none/x-forwarded").get("scheme")).isEqualTo("http");
 		assertThat(results.get("none/rfc7239").get("scheme")).isEqualTo("http");
 	}
 }
@@ -0,0 +1,36 @@
 package com.ankurm.boot42;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
 /** Collects lines and writes output/NN-name.txt. The test asserts the same values it writes. */
 final class Transcript {
 	private final List<String> lines = new ArrayList<>();
 	private final Path file;
 	Transcript(String name) {
 		String v = System.getProperty("boot.label", "4.2.0-M2");
 		String suffix = v.equals("4.2.0-M2") ? "" : "-on-" + v;
 		this.file = Path.of("output", name + suffix + ".txt");
 		line("# " + name + "  (Spring Boot " + v + ", JDK " + Runtime.version().feature() + ")");
 	}
 	Transcript line(String s) {
 		lines.add(s);
 		return this;
 	}
 	void write() {
 		try {
 			Files.createDirectories(file.getParent());
 			Files.write(file, lines);
 		}
 		catch (IOException ex) {
 			throw new IllegalStateException(ex);
 		}
 	}
 }
@@ -0,0 +1,2 @@
 target/
 *.class
@@ -0,0 +1,100 @@
 # core-beans
 Companion project for three articles on **[ankurm.com](https://ankurm.com)**.
 | Article | What it demonstrates |
 |---|---|
 | [Spring Bean Scopes: Singleton, Prototype, Request, Session and the Prototype-in-Singleton Trap](https://ankurm.com/spring-bean-scopes-singleton-prototype-request-session-prototype-in-singleton-trap/) | instance counts for every scope, five ways to get a fresh prototype inside a singleton, a singleton that leaks one caller's data into another's, and request scope without a proxy failing at start-up |
 | [Spring Bean Lifecycle in Boot 4: @PostConstruct, InitializingBean, SmartLifecycle and Shutdown Order](https://ankurm.com/spring-bean-lifecycle-postconstruct-smartlifecycle-shutdown-order/) | every callback in order from a real run, `@PostConstruct` running before the proxy exists, the non-static `BeanPostProcessor` warning, `SmartLifecycle` phases measured, and a request in flight during graceful shutdown with virtual threads |
 | [Circular Dependencies in Spring Boot 4: Why Startup Fails and 4 Ways to Fix It](https://ankurm.com/spring-boot-4-circular-dependencies-startup-fails-4-fixes/) | the start-up failure report for a three-service ring, the creation order behind it, what `allow-circular-references` does and does not repair (a half-built bean, `@Async` versus `@Cacheable`, an INFO line that swallows an exception), and four fixes run side by side: redesign, events, `@Lazy`, `ObjectProvider` |
 Every console block, exception message and count quoted in those articles came out of `output/`,
 and every file there is regenerated by one script. Most are written by the test suite, so if a
 claim stops being true the build goes red.
 There is deliberately **no `docs/` folder**: the deeper material lives in collapsible "going
 deeper" sections inside the articles themselves, next to the paragraph each one extends.
 ## Versions
 | | |
 |---|---|
 | Spring Boot | 4.1.1 |
 | Spring Framework | 7.0.9 |
 | JDK | 25 (Temurin 25.0.4.1+1) |
 | Maven | 3.9 |
 ## Quickstart
 ```bash
 export JAVA_HOME=/path/to/jdk-25
 mvn test                       # runs the scenarios and rewrites the test-written files in output/
 ./scripts/run-all.sh           # everything, including the script-captured files
 ```
 ## Source layout
 | Package | What it holds |
 |---|---|
 | `scopes/` | singleton, `@Lazy`, prototype, scoped-prototype and the five ways a singleton can obtain a prototype; the shared-state greeter |
 | `web/` | `@RequestScope`, `@SessionScope`, `@ApplicationScope` beans and a diagnostic `/scopes` controller, plus the un-proxied request bean that fails at start-up |
 | `lifecycle/` | `KitchenSink` (every callback), the post-processor traps, `PhasedWorker` and `NeverStops` for `SmartLifecycle` |
 | `shutdown/` | a web application with a `/slow` endpoint and two `SmartLifecycle` beans at different phases |
 | `cycles/` | one package per scenario: `broken/` (the three-service ring), `allowed/` (field cycles with the flag on), `redesign/`, `events/`, `lazy/` and `provider/` (the four fixes), `beanmethods/` (a cycle written as `@Bean` methods) |
 ## Endpoints
 Both endpoints exist only to be called by the tests. They have no authorisation. Delete them before shipping.
 | Endpoint | Application | Purpose |
 |---|---|---|
 | `GET /scopes` | `WebScopesApp` | request, session and application instance serials, and the injected proxy class |
 | `GET /slow?ms=1500` | `ShutdownApp` | sleeps, so a request can be in flight when the context closes |
 ## Captured output
 Files 01-17 and 19-35 (tests) and 18 (`capture-metadata.sh`). Timing rows assert coarse thresholds, not exact milliseconds; treat them as indicative.
 | File | What it shows |
 |---|---|
 | [`01-instance-counts.txt`](output/01-instance-counts.txt) | How many instances did the container really construct? |
 | [`02-prototype-destroy.txt`](output/02-prototype-destroy.txt) | @PreDestroy on a singleton and on a prototype, then context.close() |
 | [`03-prototype-in-singleton.txt`](output/03-prototype-in-singleton.txt) | A singleton calls use() five times. How many prototype instances did it touch? |
 | [`04-singleton-thread-safety.txt`](output/04-singleton-thread-safety.txt) | Two threads call the same singleton; a latch forces the interleaving |
 | [`05-web-scopes.txt`](output/05-web-scopes.txt) | request, session and application scope over real HTTP |
 | [`06-request-scope-without-proxy.txt`](output/06-request-scope-without-proxy.txt) | A request-scoped bean (no proxy) injected into a singleton |
 | [`07-full-callback-order.txt`](output/07-full-callback-order.txt) | Every callback for one bean, from constructor to the last destroy hook (SpringApplication, no web server) |
 | [`08-non-static-bpp-warning.txt`](output/08-non-static-bpp-warning.txt) | A BeanPostProcessor declared with a non-static @Bean method |
 | [`09-postconstruct-before-proxy.txt`](output/09-postconstruct-before-proxy.txt) | @PostConstruct runs before the @Async proxy exists |
 | [`10-postconstruct-failure.txt`](output/10-postconstruct-failure.txt) | An exception thrown from @PostConstruct |
 | [`11-smartlifecycle-phases.txt`](output/11-smartlifecycle-phases.txt) | Three SmartLifecycle beans registered in the order 300, 100, 200 |
 | [`12-blocking-vs-async-stop.txt`](output/12-blocking-vs-async-stop.txt) | Three SmartLifecycle beans in the SAME phase, each needing 400 ms to stop |
 | [`13-plain-lifecycle.txt`](output/13-plain-lifecycle.txt) | Lifecycle vs SmartLifecycle: who starts at refresh()? |
 | [`14-shutdown-timeout.txt`](output/14-shutdown-timeout.txt) | A SmartLifecycle whose stop(callback) never calls the callback, timeout 500 ms |
 | [`15-smartlifecycle-beans-in-boot.txt`](output/15-smartlifecycle-beans-in-boot.txt) | Every SmartLifecycle bean in a Boot web application, highest phase (stops first) at the top |
 | [`16-graceful-shutdown-in-flight.txt`](output/16-graceful-shutdown-in-flight.txt) | A /slow?ms=1500 request is in flight when the context closes |
 | [`17-worker-phase-vs-web-server.txt`](output/17-worker-phase-vs-web-server.txt) | SmartLifecycle beans with the default phase and with phase 1000, while a request is in flight |
 | [`18-property-defaults.txt`](output/18-property-defaults.txt) | Property defaults read from spring-configuration-metadata.json (Boot 4.1.1 jars) |
 | [`19-bean-post-processors.txt`](output/19-bean-post-processors.txt) | The BeanPostProcessors registered in a plain Spring Boot context, in the order they run |
 | [`20-boot-cycle-failure-report.txt`](output/20-boot-cycle-failure-report.txt) | Three constructor-injected services in a ring: what Spring Boot prints when start-up fails |
 | [`21-cycle-exception-and-creation-order.txt`](output/21-cycle-exception-and-creation-order.txt) | The exception behind the report, and the order in which the container started creating beans |
 | [`22-bean-method-cycle-failure-report.txt`](output/22-bean-method-cycle-failure-report.txt) | A two-bean cycle written as `@Bean` methods |
 | [`23-lazy-initialization-hides-the-cycle.txt`](output/23-lazy-initialization-hides-the-cycle.txt) | `spring.main.lazy-initialization=true` on the same ring: it starts, then fails on first use |
 | [`24-allow-circular-half-built-bean.txt`](output/24-allow-circular-half-built-bean.txt) | A field cycle with the flag off and on: what each `@PostConstruct` sees |
 | [`25-allow-circular-async-raw-reference.txt`](output/25-allow-circular-async-raw-reference.txt) | The same cycle with `@Async`: repaired silently at start-up, a raw-version error under lazy initialisation |
 | [`26-allow-circular-cacheable-early-proxy.txt`](output/26-allow-circular-cacheable-early-proxy.txt) | The same cycle with `@Cacheable`: the injected reference is the proxy |
 | [`27-fix-redesign.txt`](output/27-fix-redesign.txt) | Fix 1: extract the one thing the second bean needed |
 | [`28-fix-events.txt`](output/28-fix-events.txt) | Fix 2: an event instead of a call, and what the publisher sees when the listener throws |
 | [`29-fix-lazy.txt`](output/29-fix-lazy.txt) | Fix 3: `@Lazy` on the parameter, and the proxy class that arrives |
 | [`30-fix-object-provider.txt`](output/30-fix-object-provider.txt) | Fix 4: `ObjectProvider`, resolving in the constructor, and a final class |
 | [`31-lazy-on-a-final-class.txt`](output/31-lazy-on-a-final-class.txt) | `@Lazy` on a parameter whose type is a final class |
 | [`32-lazy-injection-point-versus-lazy-bean.txt`](output/32-lazy-injection-point-versus-lazy-bean.txt) | `@Lazy` on the injection point versus on the bean, with a target that cannot be built |
 | [`33-dispatcher-handler-cycle.txt`](output/33-dispatcher-handler-cycle.txt) | A cycle through `List<Handler>` and its `ObjectProvider` repair |
 | [`34-depends-on-cycle.txt`](output/34-depends-on-cycle.txt) | `@DependsOn` in both directions: no injection involved |
 | [`35-lazy-used-during-construction.txt`](output/35-lazy-used-during-construction.txt) | `@Lazy` on the parameter, but the bean calls the dependency from `@PostConstruct` |
 | [`36-main-property-defaults.txt`](output/36-main-property-defaults.txt) | The defaults of `spring.main.allow-circular-references` and `spring.main.lazy-initialization`, from Boot's own metadata |
 | [`37-early-reference-bytecode.txt`](output/37-early-reference-bytecode.txt) | Which post-processors hand out an early reference, and the `BeanCurrentlyInCreationException` handler in `preInstantiateSingleton` |
 ## Licence
 MIT, see the repository root.
@@ -0,0 +1,14 @@
 # How many instances did the container really construct?
 right after refresh():
  singleton instances : 1
  @Lazy singleton     : 0
  prototype           : 0
 after getBean() twice for singleton and lazy, three times for prototype:
  singleton instances : 1   same object both times: true
  @Lazy singleton     : 1   same object both times: true
  prototype           : 3   serials: 1, 2, 3
 two separate contexts, each with SingletonBean:
  singleton instances : 2   same object across contexts: false
@@ -0,0 +1,4 @@
 # @PreDestroy on a singleton and on a prototype, then context.close()
 prototype instances created: 1
 callbacks after close(): [singleton @PreDestroy called]
@@ -0,0 +1,11 @@
 # A singleton calls use() five times. How many prototype instances did it touch?
 how the prototype is obtained      serials seen           instances built
 ---------------------------------- ---------------------- ---------------
 constructor injection (naive)      [1, 1, 1, 1, 1]        1
 ObjectProvider.getObject()         [1, 2, 3, 4, 5]        5
@Lookup method                     [1, 2, 3, 4, 5]        5
 scoped proxy (TARGET_CLASS)        [1, 2, 3, 4, 5]        5
 ApplicationContext.getBean()       [1, 2, 3, 4, 5]        5
 ProxyConsumer's injected reference is a com.ankurm.corebeans.scopes.ScopedPrototypeBean$$SpringCGLIB$$0
@@ -0,0 +1,4 @@
 # Two threads call the same singleton; a latch forces the interleaving
 UnsafeGreeter (state in a field)   : alice's call returned "Hello, bob"
 SafeGreeter   (state in a local)   : alice's call returned "Hello, alice"
@@ -0,0 +1,10 @@
 # request, session and application scope over real HTTP
 client     response
 A #1       request=1 session=1 application=1 injectedRequestClass=RequestBean$$SpringCGLIB$$0
 A #2       request=2 session=1 application=1 injectedRequestClass=RequestBean$$SpringCGLIB$$0
 A #3       request=3 session=1 application=1 injectedRequestClass=RequestBean$$SpringCGLIB$$0
 B #1       request=4 session=2 application=1 injectedRequestClass=RequestBean$$SpringCGLIB$$0
 B #2       request=5 session=2 application=1 injectedRequestClass=RequestBean$$SpringCGLIB$$0
 instances constructed: request=5 session=2 application=1
@@ -0,0 +1,6 @@
 # A request-scoped bean (no proxy) injected into a singleton
 top exception : org.springframework.beans.factory.UnsatisfiedDependencyException
 top message   : Error creating bean with name 'brokenRequestConsumer': Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'brokenRequestConsumer.RawRequestBean': Scope 'request' is not active for the current thread; consider defining a scoped proxy for this bean if you intend to refer to it from a singleton
 root cause    : java.lang.IllegalStateException: No thread-bound request found: Are you referring to request attributes outside of an actual web request, or processing a request outside of the originally receiving thread? If you are actually operating within a web request and still receive this message, your code is probably running outside of DispatcherServlet: In this case, use RequestContextListener or RequestContextFilter to expose the current request.
@@ -0,0 +1,26 @@
 # Every callback for one bean, from constructor to the last destroy hook (SpringApplication, no web server)
 === startup ===
 constructor
 setter injection (@Autowired setDependency)
 BeanNameAware.setBeanName("kitchenSink")
 BeanFactoryAware.setBeanFactory
 ApplicationContextAware.setApplicationContext
 BeanPostProcessor.postProcessBeforeInitialization
@PostConstruct
 InitializingBean.afterPropertiesSet
@Bean(initMethod = "customInit")
 BeanPostProcessor.postProcessAfterInitialization
 SmartInitializingSingleton.afterSingletonsInstantiated
 SmartLifecycle.start (phase 2147483647)
 ContextRefreshedEvent
 ApplicationStartedEvent
 ApplicationRunner.run
 ApplicationReadyEvent
 === ctx.close() ===
 ContextClosedEvent
 SmartLifecycle.stop
@PreDestroy
 DisposableBean.destroy
@Bean(destroyMethod = "customDestroy")
@@ -0,0 +1,3 @@
 # A BeanPostProcessor declared with a non-static @Bean method
 2026-09-24T10:28:59.979+05:30  WARN 3358 --- [core-beans] [           main] trationDelegate$BeanPostProcessorChecker : Bean 'nonStaticProcessorConfig' of type [com.ankurm.corebeans.lifecycle.NonStaticProcessorConfig$$SpringCGLIB$$0] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying). The currently created BeanPostProcessor [quietProcessor] is declared through a non-static factory method on that class; consider declaring it as static instead.
@@ -0,0 +1,4 @@
 # @PostConstruct runs before the @Async proxy exists
@PostConstruct sees this = com.ankurm.corebeans.lifecycle.AsyncMailer, isAopProxy(this) = false
 the bean other code receives : com.ankurm.corebeans.lifecycle.AsyncMailer$$SpringCGLIB$$0
@@ -0,0 +1,6 @@
 # An exception thrown from @PostConstruct
 context started: false
 top exception : org.springframework.beans.factory.BeanCreationException
 top message   : Error creating bean with name 'failingInit': Invocation of init method failed
 root cause    : java.lang.IllegalStateException: cache warm-up failed
@@ -0,0 +1,10 @@
 # Three SmartLifecycle beans registered in the order 300, 100, 200
 === refresh() ===
 start A (phase 100)
 start B (phase 200)
 start C (phase 300)
 === close() ===
 stop  C (phase 300)
 stop  B (phase 200)
 stop  A (phase 100)
@@ -0,0 +1,4 @@
 # Three SmartLifecycle beans in the SAME phase, each needing 400 ms to stop
 stop(Runnable) blocks (the default)  : close() took >= 1100 ms (sequential)
 stop(Runnable) returns immediately   : close() took < 800 ms (concurrent)
@@ -0,0 +1,4 @@
 # Lifecycle vs SmartLifecycle: who starts at refresh()?
 after refresh() : events=[] isRunning=false
 after start()   : events=[PlainLifecycle.start] isRunning=true
@@ -0,0 +1,4 @@
 # A SmartLifecycle whose stop(callback) never calls the callback, timeout 500 ms
 close() returned after roughly the timeout: true
 2026-09-24T10:28:58.263+05:30  INFO 3358 --- [core-beans] [           main] o.s.c.support.DefaultLifecycleProcessor  : Shutdown phase 2147483647 ends with 1 bean still running after timeout of 500ms: [neverStops]
@@ -0,0 +1,11 @@
 # Every SmartLifecycle bean in a Boot web application, highest phase (stops first) at the top
 phase          bean name                          class
 2147483647     earlyWorker                        EarlyWorker
 2147482623     webServerGracefulShutdown          WebServerGracefulShutdownLifecycle
 2147481599     webServerStartStop                 WebServerStartStopLifecycle
 1073741823     applicationTaskExecutor            ThreadPoolTaskExecutor
 1000           lateWorker                         LateWorker
 -2147483647    springBootLoggingLifecycle         Lifecycle
 SmartLifecycle.DEFAULT_PHASE = 2147483647
@@ -0,0 +1,7 @@
 # A /slow?ms=1500 request is in flight when the context closes
 settings                                     the client saw                                       close() blocked                  handler ran to the end
 -------------------------------------------- ---------------------------------------------------- -------------------------------- ----------------------
 server.shutdown=graceful, virtual threads    HTTP 200: finished after 1500 ms, virtual thread = true >= 1 s (waited for the request)  yes
 server.shutdown=graceful, platform threads   HTTP 200: finished after 1500 ms, virtual thread = false >= 1 s (waited for the request)  yes
 server.shutdown=immediate, virtual threads   FAILED: connection dropped, no response              >= 1 s (waited for the request)  yes
@@ -0,0 +1,5 @@
 # SmartLifecycle beans with the default phase and with phase 1000, while a request is in flight
 EarlyWorker.stop  (phase 2147483647): requests still in flight = 1
 LateWorker.stop   (phase 1000): requests still in flight = 0
 the client saw: HTTP 200: finished after 1500 ms, virtual thread = true
@@ -0,0 +1,5 @@
 # Property defaults read from spring-configuration-metadata.json (Boot 4.1.1 jars)
 spring.lifecycle.timeout-per-shutdown-phase    type=java.time.Duration                       default=30s
 spring.threads.virtual.enabled                 type=java.lang.Boolean                        default=False
 server.shutdown                                type=org.springframework.boot.web.server.Shutdown default=graceful
@@ -0,0 +1,9 @@
 # The BeanPostProcessors registered in a plain Spring Boot context, in the order they run
 1  org.springframework.context.support.ApplicationContextAwareProcessor
 2  org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor
 3  org.springframework.context.support.PostProcessorRegistrationDelegate$BeanPostProcessorChecker
 4  com.ankurm.corebeans.lifecycle.TracingPostProcessor
 5  org.springframework.context.annotation.CommonAnnotationBeanPostProcessor
 6  org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor
 7  org.springframework.context.support.ApplicationListenerDetector
@@ -0,0 +1,22 @@
 # Three constructor-injected services in a ring: what Spring Boot 4.1.1 prints when start-up fails
 ***************************
 APPLICATION FAILED TO START
 ***************************
 Description:
 The dependencies of some of the beans in the application context form a cycle:
 ┌─────┐
 |  notificationService defined in file [<core-beans>/target/classes/com/ankurm/corebeans/cycles/broken/NotificationService.class]
 ↑     ↓
 |  orderService defined in file [<core-beans>/target/classes/com/ankurm/corebeans/cycles/broken/OrderService.class]
 ↑     ↓
 |  paymentService defined in file [<core-beans>/target/classes/com/ankurm/corebeans/cycles/broken/PaymentService.class]
 └─────┘
 Action:
 Relying upon circular references is discouraged and they are prohibited by default. Update your application to remove the dependency cycle between beans. As a last resort, it may be possible to break the cycle automatically by setting spring.main.allow-circular-references to true.
@@ -0,0 +1,14 @@
 # The exception behind the report, and the order in which the container started creating beans
 --- exception classes, outermost first ---
 UnsatisfiedDependencyException -> UnsatisfiedDependencyException -> UnsatisfiedDependencyException -> BeanCurrentlyInCreationException
 --- root cause ---
 org.springframework.beans.factory.BeanCurrentlyInCreationException
 Error creating bean with name 'notificationService': Requested bean is currently in creation: Is there an unresolvable circular reference or an asynchronous initialization dependency?
 --- creation order (one line per bean the container began to create) ---
 start creating notificationService
 start creating orderService
 start creating paymentService
@@ -0,0 +1,20 @@
 # A two-bean cycle written as @Bean methods: the report names the configuration class instead of a class file
 ***************************
 APPLICATION FAILED TO START
 ***************************
 Description:
 The dependencies of some of the beans in the application context form a cycle:
 ┌─────┐
 |  clock defined in com.ankurm.corebeans.cycles.beanmethods.BeanMethodCycle
 ↑     ↓
 |  calendar defined in com.ankurm.corebeans.cycles.beanmethods.BeanMethodCycle
 └─────┘
 Action:
 Relying upon circular references is discouraged and they are prohibited by default. Update your application to remove the dependency cycle between beans. As a last resort, it may be possible to break the cycle automatically by setting spring.main.allow-circular-references to true.
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Claude	008211f2fa	Add file-transfer module: multipart limits, filename handling, Range downloads, streaming under -Xmx64m, S3 presigned URLs Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01VRLbHYdXVEBzGVhYq3pz4q	2026-10-17 15:41:24 +00:00
Claude	b9388053c4	Add rest-client-test module: @RestClientTest on Boot 4.1, Jackson 3 by default, and the RestClient-vs-RestTemplate root-URI matching trap (post #49 )	2026-10-08 16:40:51 +00:00
Claude	4370ac7fdf	Correct post #45 : Flyway and Liquibase DO run under @DataJpaTest by default The previous commit's FlywayDoesNotRunUnderPlainDataJpaTestTest and FlywayRunsWhenExplicitlyImportedTest rested on a false premise: that none of @DataJpaTest's four documented meta-annotations import FlywayAutoConfiguration, so migrations never run under the slice. That reading of the four .imports manifests is accurate but incomplete. @AutoConfigureJdbc is itself meta-annotated with @AutoConfigureDataSourceInitialization (new in Boot 4.0), and Spring's ImportAutoConfigurationImportSelector walks the full meta-annotation tree transitively. That fifth annotation's own .imports resource is loaded via ClassLoader.getResources(), which merges same-named files from every jar on the classpath -- spring-boot-jdbc-test, spring-boot-flyway and spring-boot-liquibase each ship one at the identical path, contributing DataSourceInitializationAutoConfiguration, FlywayAutoConfiguration and LiquibaseAutoConfiguration respectively. Replaced the two wrong-premise test classes with FlywayRunsByDefaultTest (proves the bean is present and the migration actually ran) and ExplicitFlywayImportIsRedundantTest (proves the old "add the import yourself" advice is harmless but unnecessary on Boot 4.1). Added javap/unzip evidence for the new mechanism to docs/output, re-captured the full test run (9 tests, 1 clean skip), corrected README's test table, and closed a second, unrelated gap: the unzip -l listing quoted in the @ServiceConnection section had no matching captured transcript -- it does now.	2026-10-08 12:35:04 +00:00
Claude	97f946136b	Add data-jpa-testcontainers module: @DataJpaTest's default substitution, the Flyway-never-runs trap, and @ServiceConnection on Testcontainers 2.0.5 (post #45 )	2026-10-08 11:52:08 +00:00
Claude	5e4d481c02	Add rest-test-client module: RestTestClient across all four binding modes, TestRestTemplate relocation, gzip-hiding HTTP client surprise (post #44 )	2026-10-08 09:40:13 +00:00
Claude	5851521420	Add testing-no-containers module: WireMock, MockWebServer, @MockitoBean/@MockitoSpyBean (post #43 )	2026-10-08 06:19:52 +00:00
Claude	f736108067	Add kotlin module: null safety, coroutines, allopen/noarg, JSpecify interop (post #42 )	2026-10-08 05:35:15 +00:00
Claude	83d245e726	hexagonal: capture the real missing-scan-base-packages failure as a transcript A follow-up to the hexagonal module commit: the post's self-correction pass caught a console block quoting that exception from memory instead of a committed transcript, so this captures it for real (by removing @EnableJpaRepositories/@EntityScan, running the test, and restoring them) and links the README to it. A regular git commit --amend + force-push would have kept this at one commit for the module, matching every other module in this repo, but this session's git safety controls do not allow a force-push, so this lands as its own small commit instead.	2026-10-03 20:35:59 +00:00
Claude	fd6d0fa1e7	Add the hexagonal module: Hexagonal Architecture (Ports and Adapters) in Spring Boot 4	2026-10-03 20:28:16 +00:00
asmhatreandClaude Sonnet 5	ae681f85c4	Add batch-5-to-6 module: Spring Batch 5.2 to 6.0 migration on Boot 3.5 to 4.1 Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Gth99spB1CzQmBFofXmU4Z	2026-09-28 09:09:50 +00:00
asmhatreandClaude Sonnet 5	804c33f0d5	Add gradle9 module: Spring Boot 4 build migrated from Gradle 8 to Gradle 9 Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Gth99spB1CzQmBFofXmU4Z	2026-09-28 09:00:03 +00:00
Claude	b4b43b94bf	Add openrewrite module: Boot 2.7 to 3.5 to 4.0 upgrade with OpenRewrite recipes, leftovers and CI gate Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Gth99spB1CzQmBFofXmU4Z	2026-09-28 08:40:08 +00:00
Claude	e4f927d7af	Add jakarta-ee-11 module: Jakarta EE 10 vs 11 API comparison against Spring Boot 4.1.1 Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Gth99spB1CzQmBFofXmU4Z	2026-09-28 08:40:07 +00:00
Claude	acd63e658b	Add boot42-preview module: Spring Boot 4.2.0-M2 vs 4.1.1 forwarded headers, AMQP starters, buildpack cache, RestTemplate removal warnings Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Gth99spB1CzQmBFofXmU4Z	2026-09-28 08:40:07 +00:00
Claude	3e2029ab3a	Add aot-cache module: the JDK 25 AOT cache on Spring Boot 4.1 vs AppCDS, Spring AOT and GraalVM native A Spring Boot 4.1.1 order service started 12 ways (plain and extracted jar, Spring AOT output, AppCDS, AOT cache trained with and without traffic, JDK 27, native image), ten interleaved rounds each, with first-request latency; 24 cache-mismatch cases; Docker layer arithmetic. Transcripts are in output/ (no docs/ folder). Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01TF9JWFvJSNm6HVzswzZU5a	2026-09-24 16:44:16 +00:00
Claude	fa4205f631	README: list the custom-starter, core-events, multi-datasource and i18n modules and the circular-dependencies article Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Uu7q8vPeREyT4218EJPzz1	2026-09-24 10:01:37 +00:00
Claude	a2cc7bbd08	i18n: say only what was observed about the leaked JVM default locale Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Uu7q8vPeREyT4218EJPzz1	2026-09-24 10:01:36 +00:00
Claude	2cbf31e7d5	Add i18n module: MessageSource, LocaleResolver and localized ProblemDetail English, Marathi and Hindi bundles behind one small web app, with tests that run it on a real port and write the transcripts (01-11) quoted in the article, plus a jar-metadata capture (12). Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Uu7q8vPeREyT4218EJPzz1	2026-09-24 09:54:55 +00:00
Claude	e59ff029a1	Add multi-datasource module: two databases with per-database DataSource, Flyway, EntityManagerFactory and transaction manager on Boot 4.1 Working setup plus one small application per way of getting it wrong (no @Primary, @Primary only, url vs jdbc-url, wrong repository package, Flyway auto-configuration), plain vs named @Transactional, and ChainedTransactionManager with a failing commit. Transcripts are written by the tests. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Uu7q8vPeREyT4218EJPzz1	2026-09-24 09:38:27 +00:00
Claude	d6b76c57db	Add core-events module: @EventListener, @TransactionalEventListener phases and async listeners on Boot 4.1 Thirteen captured transcripts: a listener is a blocking method call, ordering and chaining, SpEL conditions, generic-event erasure, every transaction phase on commit and rollback, what an AFTER_COMMIT listener can write, which exceptions reach the publisher, async listeners on platform and virtual threads, and the annotations behind Spring Modulith's @ApplicationModuleListener. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Uu7q8vPeREyT4218EJPzz1	2026-09-24 07:08:47 +00:00
Claude	c418589251	Add custom-starter module: a Boot 4 auto-configuration starter with conditions, metadata and runner tests Two-jar starter (autoconfigure + starter), a demo app, and 17 captured transcripts covering AutoConfiguration.imports, @ConditionalOn*, ordering, optional Jackson 3 integration, configuration metadata and the Boot 4 module split. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Uu7q8vPeREyT4218EJPzz1	2026-09-24 06:53:07 +00:00
Claude	d6a2e1a5f2	Add cycles to core-beans: the circular-dependency failure report, what allow-circular-references repairs and hides, and four fixes on Boot 4.1 Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01Uu7q8vPeREyT4218EJPzz1	2026-09-24 06:29:14 +00:00
Claude	51f3ecd5da	Add core-beans: bean scopes, the prototype-in-singleton trap, lifecycle callback order and graceful shutdown phases on Boot 4.1 Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01JoVmf2fWvcpoXndcDSwRf7	2026-09-24 04:59:41 +00:00
Claude	9825efa081	Add core-di: constructor vs setter vs field injection and @Autowired candidate resolution on Boot 4.1 Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01JoVmf2fWvcpoXndcDSwRf7	2026-09-24 04:59:40 +00:00
		`@@ -0,0 +1,2 @@`
							`spring.application.name=aot-cache`
							`management.endpoints.web.exposure.include=health`
		`@@ -0,0 +1,2 @@`
							`# 06-restclient-replacement (javac -Xlint:deprecation on the RestClient version, Spring Boot 4.2.0-M2)`
							`javac finished; lines above this one are warnings (none means a clean compile)`
		`@@ -0,0 +1,3 @@`
							`# A BeanPostProcessor declared with a non-static @Bean method`

							`2026-09-24T10:28:59.979+05:30 WARN 3358 --- [core-beans] [ main] trationDelegate$BeanPostProcessorChecker : Bean 'nonStaticProcessorConfig' of type [com.ankurm.corebeans.lifecycle.NonStaticProcessorConfig$$SpringCGLIB$$0] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying). The currently created BeanPostProcessor [quietProcessor] is declared through a non-static factory method on that class; consider declaring it as static instead.`