asmhatreandClaude Sonnet 5
a875bea55a
While writing the article, chapter 14's first failure mode (a concurrent statement seeing "Table CUSTOMERS not found" while DROP COLUMN runs) was described from the live load-generator run but had no dedicated, committed reproduction of its own - CustomerService's own retry would silently absorb it if triggered through the service layer. DdlCollisionExceptionTest reproduces it directly at the raw JDBC level, and the chapter and README now link to its captured transcript. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_019Fb7vW8vLyLKngBc4R3huA
spring-boot-demo
Companion code for the Spring Boot articles on ankurm.com.
One directory per article. Each is a self-contained Maven project with its own README.md,
numbered documentation chapters under docs/, and captured real output under docs/output/
that a single script regenerates. Every figure quoted in an article came out of one of those
files.
| Directory | Article | What it demonstrates |
|---|---|---|
actuator-in-production/ |
Spring Boot Actuator in Production | endpoint exposure defaults, securing Actuator, custom health indicators and how they hang |
spring-boot-startup-time/ |
Why Your Spring Boot App Takes 8 Seconds to Start | BufferingApplicationStartup, JFR startup events, self time vs total time, the classpath-scan tax, the JDK 25 AOT cache |
configuration-properties/ |
@ConfigurationProperties vs @Value in Spring Boot 4 | relaxed binding measured three ways, record constructor binding, validation, IDE metadata generation |
profiles-and-config/ |
Spring Boot Profiles Done Right | the precedence stack made visible, config trees and ConfigMaps, why a profile file loses to an environment variable |
spring-aop/ |
Spring AOP Explained | every pointcut designator with real matches, JDK vs CGLIB proxies, six aspects that do not fire |
docker-images/ |
Dockerizing Spring Boot 4: Layered Jars, Buildpacks, Distroless and Image Size Benchmarks | one service packaged nine ways and measured: size on disk and pushed, rebuild delta, startup, PID 1 and signals, jlink, the JDK 25 AOT cache |
kubernetes-deployment/ |
Deploying Spring Boot 4 on Kubernetes | probe groups under a dependency outage, graceful shutdown under load four ways, JVM ergonomics per pod shape, CPU limits throttling GC, HPA on a Micrometer metric |
problem-details/ |
Global Exception Handling with ProblemDetail (RFC 9457) in Spring Boot 4 | thirteen failures under five handling setups, validation errors, i18n, content negotiation, errors outside MVC, silent 500s, decoding on the client |
resilience/ |
Spring Framework 7's Built-in Resilience: @Retryable, @ConcurrencyLimit, and What's Left for Resilience4j | @Retryable and @ConcurrencyLimit counted invocation by invocation, retries inside transactions, where Resilience4j still earns its place, migrating from Spring Retry |
caching/ |
The Spring Cache Abstraction: @Cacheable, @CacheEvict, Key Generators and the Self-Invocation Trap | the self-invocation trap measured four ways, the key collision SimpleKeyGenerator makes easy, eviction timing under a thrown exception, a rollback the cache keeps, and where this sits next to Hibernate's L2 cache |
spring-batch/ |
Spring Batch on Boot 4.1: Jobs, Steps, Chunk Processing and Restartability | a job that fails mid-chunk and resumes exactly where it left off across two separate JVMs, skip vs. restart on the same poisoned row, the resourceless job repository that forgets a restart ever happened, and the chunk(int) vs chunk(int, tx) builder split |
spring-batch-partitioning/ |
Spring Batch Partitioning and Parallel Steps: Scaling a 10-Million-Row Job | the real grid-size sweep at 10M and 300K rows (best speedup 1.42x, on 2 cores), MultiResourcePartitioner ignoring gridSize entirely, a rejected partition's StepExecution stuck at STARTING forever, and Spring Batch 6.0's new JobOperator#recover unsticking it |
db-migrations-flyway-liquibase/ |
Flyway vs Liquibase for Spring Boot 4: Migrations, Rollbacks and Baselines | Flyway Community's undo throwing FlywayRedgateEditionRequiredException at runtime, a real Liquibase 5.0.3 filename-caching defect that produces a phantom successful run, Liquibase's 10-second default lock-poll rate versus Flyway's near-instant row lock, the FSL license change and its ASF/Keycloak fallout, and what actually happens when both tools are enabled against one database |
db-migrations-expand-contract/ |
Zero-Downtime Database Migrations: Expand-Contract in Practice with Spring Boot | a real 4-deploy rolling sequence against two live replicas with a load generator proving 99.98% success, H2's AUTO_SERVER single-point-of-failure trap, a NOT NULL constraint that fails every Stage 4 insert, and ALTER TABLE silently dropping a concurrently committed row with no exception thrown |
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
categories.
Running any of them
Each project needs a JDK 25 and Maven 3.9. docker-images also needs Docker, and
kubernetes-deployment Docker plus a Kubernetes cluster; their READMEs list the rest:
cd <directory>
export JAVA_HOME=/path/to/jdk-25
mvn -DskipTests package
./scripts/run-all.sh # regenerate every transcript under docs/output/
Licence
MIT — see LICENSE.