Ankur Mhatre
86246dc860
configuration-properties/ @ConfigurationProperties vs @Value on Spring Boot 4.1.1. The relaxed-binding matrix is generated by binding each spelling rather than transcribed, and re-checked against real processes -- the in-process probe was wrong twice before it was right. Records the three findings that came out of it: @Value does get relaxed resolution inside Spring Boot (Boot attaches ConfigurationPropertySources), the configuration processor silently stops generating metadata on JDK 23+ when declared as a plain dependency, and @Valid is not what makes nested constraints run. profiles-and-config/ Precedence, profiles, spring.config.import and config trees. /precedence reports every source holding a property in rank order with file and line, which turns "my profile file had no effect" into a two-line answer. Also pins the counterintuitive one: an imported file outranks the file that imported it. spring-aop/ Designators, proxy types, and aspects that do not fire. One advice per supported designator so the reference table is generated from real matches; all fourteen unsupported designators fed to the parser. Two corrections to the reference documentation: unsupported designators throw UnsupportedPointcutPrimitiveException (extends RuntimeException, not IllegalArgumentException), and spring-boot-starter-aop was renamed to spring-boot-starter-aspectj in Boot 4. 19 contract tests across the three modules, 15 captured transcripts, all regenerated by scripts/run-all.sh. Verified on Spring Boot 4.1.1, Spring Framework 7.0.9, JDK 25.0.4.1. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Gip4srpzMwjgoba6uEfbr5
Spring AOP: designators, proxies, and aspects that do not fire
Companion project for Spring AOP Explained on ankurm.com.
Two halves. One set of aspects that work — one advice per pointcut designator, so the reference table is generated from real matches. One set that does not fire, each for a different reason, each paired with its fix.
Versions
| Spring Boot | 4.1.1 |
| Spring Framework | 7.0.9 |
| AspectJ weaver | 1.9.25.1 |
| JDK | Eclipse Temurin 25.0.4.1 (LTS) |
Read this before copying a dependency block
In Spring Boot 3 the starter was spring-boot-starter-aop. In Spring Boot 4 it is
spring-boot-starter-aspectj. The old artifact's last publication is 4.0.0-M2 and its
last GA is 3.5.16, so a pre-4 dependency block fails resolution with a missing-version error.
Quickstart
export JAVA_HOME=/path/to/jdk-25
mvn -DskipTests package
./scripts/run-all.sh # regenerate every transcript in docs/output/
mvn test # 6 contract tests
Endpoints
| Endpoint | Purpose |
|---|---|
GET /aop/proxies |
per bean: proxied or not, which kind, and the advisor list |
GET /aop/designators |
exercises every advised method, reports what each designator matched |
GET /aop/parser |
feeds supported and unsupported expressions to the pointcut parser |
GET /aop/broken |
runs the failure gallery and reports that nothing fired |
Documentation
- What Spring AOP actually is
- The designator reference
- JDK dynamic proxies and CGLIB
- Advice types and ordering
- Six aspects that do not fire
- Diagnosing a silent aspect
Captured output
| File | Produced by |
|---|---|
00-versions.txt |
scripts/demo-versions.sh |
01-designators.txt |
scripts/demo-designators.sh |
02-proxy-types.txt |
scripts/demo-proxy-types.sh |
03-broken-gallery.txt |
scripts/demo-broken-gallery.sh |
Two corrections to the reference documentation
- Unsupported designators throw
UnsupportedPointcutPrimitiveException, which extendsRuntimeExceptiondirectly — notIllegalArgumentExceptionas the docs state. Catching the documented type will not catch it. - The framework default is interface-based proxying, but Spring Boot sets
proxy-target-class=true, so you get CGLIB even for beans that implement interfaces. That changes which designators match;scripts/demo-proxy-types.shshows both.