resilience: prove spring-boot-starter-aop was renamed to spring-boot-starter-aspectj, not removed

Maven Central's maven-metadata.xml for both artifact IDs, read together, shows aop's last release is 4.0.0-M2 and aspectj's first release is 4.0.0-M3 -- a rename at a milestone boundary, not a drop. The renamed starter's own published POM depends on exactly spring-aop + aspectjweaver, the two jars this pom.xml's dependency comment already claimed were needed; this commit adds the reproducible build-break proof, the metadata/POM evidence, and a new doc chapter, and backs the corrected companion-repo links from the resilience4j- circuit-breaker-spring-boot post.
2026-09-18 08:34:06 +00:00
parent baff043748
commit 604291067e
9 changed files with 179 additions and 2 deletions
@@ -48,6 +48,7 @@ All of these are diagnostics for the article. Delete [`DemoController`](src/main
 5. [Retry and transactions](docs/05-retry-and-transactions.md)
 6. [What is left for Resilience4j](docs/06-what-is-left-for-resilience4j.md)
 7. [Migrating from spring-retry](docs/07-migrating-from-spring-retry.md)
+8. [`spring-boot-starter-aop` was renamed, not removed](docs/08-starter-aop-renamed-to-starter-aspectj.md) - also backs the sibling post [Resilience4j Circuit Breaker in Spring Boot 4.1](https://ankurm.com/resilience4j-circuit-breaker-spring-boot/)

 ## Findings worth the trip

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- NOT part of the main build (no parent module lists this directory). Exists only so
+     scripts/reproduce-starter-aop-break.sh can run `mvn compile` against it and capture
+     the real error. See docs/01-two-resilience-stacks.md. -->
+<project xmlns="http://maven.apache.org/POM/4.0.0">
+  <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>break-demo</artifactId>
+  <version>1.0.0</version>
+  <dependencies>
+    <!-- This is the dependency every pre-Boot-4 Resilience4j guide tells you to add.
+         It no longer exists past 4.0.0-M2. -->
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-aop</artifactId>
+    </dependency>
+  </dependencies>
+</project>
@@ -1,6 +1,6 @@
 # 7. Migrating from spring-retry

-[← 6. What is left for Resilience4j](06-what-is-left-for-resilience4j.md) · [Index](../README.md)
+[← 6. What is left for Resilience4j](06-what-is-left-for-resilience4j.md) · [Index](../README.md) · [8. Starter rename: aop → aspectj →](08-starter-aop-renamed-to-starter-aspectj.md)

 The spring-retry README now says the project "is no longer maintained as an open-source project"
 and "has been superseded by Spring Framework 7". Its last release on Maven Central is 2.0.13.
@@ -0,0 +1,59 @@
+← [What is left for Resilience4j](06-what-is-left-for-resilience4j.md) | [Migrating from spring-retry](07-migrating-from-spring-retry.md) →
+
+# `spring-boot-starter-aop` was renamed, not removed
+
+Every pre-Boot-4 AOP or Resilience4j guide tells you to add `spring-boot-starter-aop` when an
+annotation (`@Retryable`, `@ConcurrencyLimit`, Resilience4j's `@CircuitBreaker`, plain `@Aspect`
+beans, anything proxy-based) needs AspectJ on the classpath. On Boot 4.1, adding that dependency
+breaks the build before the application ever starts:
+
+```
+[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter-aop:jar is missing.
+```
+
+Captured by [`scripts/reproduce-starter-aop-break.sh`](../scripts/reproduce-starter-aop-break.sh)
+against the minimal [`broken-example/pom.xml`](../broken-example/pom.xml), which adds only that
+one dependency: [`00a-starter-aop-build-error.txt`](output/00a-starter-aop-build-error.txt).
+
+## It was renamed, not dropped
+
+It is tempting to read that error as "the starter is gone, assemble `spring-aop` and
+`aspectjweaver` by hand instead" -- an earlier version of the sibling post this repo also serves
+said exactly that. It is half right and half wrong. Maven Central's `maven-metadata.xml` for both
+artifact IDs, read together, settles it:
+[`00b-starter-aspectj-metadata-timeline.txt`](output/00b-starter-aspectj-metadata-timeline.txt).
+
+`spring-boot-starter-aop`'s last-ever published version is `4.0.0-M2`. `spring-boot-starter-aspectj`'s
+first-ever published version is `4.0.0-M3` -- the very next milestone in the same 4.0 line, and it
+carries straight through to the 4.0.0 GA and every 4.1.x release since. That is a rename at a
+specific milestone boundary, not an unrelated new artifact and not a starter dropped with nothing
+replacing it.
+
+The renamed starter's own published POM confirms it bundles exactly the two jars this module's
+`pom.xml` needs:
+[`00c-starter-aspectj-pom-dependencies.txt`](output/00c-starter-aspectj-pom-dependencies.txt).
+
+```xml
+<dependency>
+  <groupId>org.springframework.boot</groupId>
+  <artifactId>spring-boot-starter-aspectj</artifactId>
+</dependency>
+```
+
+is all this module adds (see [`pom.xml`](../pom.xml)) -- one line, version-managed by the parent
+POM like any other starter, resolving to `spring-aop` + `aspectjweaver` underneath. Assembling
+those two dependencies by hand still works and behaves identically, since it's what the starter
+does anyway, but there's no longer a reason to: the starter has the same name shape as every
+other Boot starter, it's just spelled `aspectj` instead of `aop` from the 4.0 line onward.
+
+<blockquote>If you're on a build that still references <code>spring-boot-starter-aop</code> after
+upgrading to Boot 4, the fix is a rename in your <code>pom.xml</code>, not a rewrite: swap the
+<code>artifactId</code> to <code>spring-boot-starter-aspectj</code> and nothing else changes.</blockquote>
+
+## Going deeper
+
+- [`pom.xml`](../pom.xml) -- this module's own dependency, with the corrected comment
+- Maven Central: [`spring-boot-starter-aop/maven-metadata.xml`](https://repo1.maven.org/maven2/org/springframework/boot/spring-boot-starter-aop/maven-metadata.xml) and [`spring-boot-starter-aspectj/maven-metadata.xml`](https://repo1.maven.org/maven2/org/springframework/boot/spring-boot-starter-aspectj/maven-metadata.xml) -- rel="nofollow"
+- [Resilience4j Circuit Breaker in Spring Boot 4.1: What It's Still For](https://ankurm.com/resilience4j-circuit-breaker-spring-boot/) -- the sibling post this same correction applies to
+
+← [What is left for Resilience4j](06-what-is-left-for-resilience4j.md) | [Migrating from spring-retry](07-migrating-from-spring-retry.md) →
@@ -0,0 +1,13 @@
+[ERROR] [ERROR] Some problems were encountered while processing the POMs:
+[ERROR] 'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter-aop:jar is missing. @ line 19, column 17
+ @ 
+[ERROR] The build could not read 1 project -> [Help 1]
+[ERROR]   
+[ERROR]   The project com.ankurm:break-demo:1.0.0 (/home/claude/work/repos/spring-boot-demo-migration/resilience/broken-example/pom.xml) has 1 error
+[ERROR]     'dependencies.dependency.version' for org.springframework.boot:spring-boot-starter-aop:jar is missing. @ line 19, column 17
+[ERROR] 
+[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
+[ERROR] Re-run Maven using the -X switch to enable full debug logging.
+[ERROR] 
+[ERROR] For more information about the errors and possible solutions, please read the following articles:
+[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/ProjectBuildingException
@@ -0,0 +1,33 @@
+Captured 2026-09-18 from repo1.maven.org (Maven Central), not an aggregator or blog.
+
+--- org/springframework/boot/spring-boot-starter-aop/maven-metadata.xml ---
+<latest>4.0.0-M2</latest>
+<release>4.0.0-M2</release>
+... version list ends at:
+  <version>3.5.16</version>
+  <version>4.0.0-M1</version>
+  <version>4.0.0-M2</version>
+</versions>
+<lastUpdated>20260625105758</lastUpdated>
+
+--- org/springframework/boot/spring-boot-starter-aspectj/maven-metadata.xml ---
+<latest>4.2.0-M1</latest>
+<release>4.2.0-M1</release>
+... version list starts at:
+  <version>4.0.0-M3</version>
+  <version>4.0.0-RC1</version>
+  <version>4.0.0-RC2</version>
+  <version>4.0.0</version>
+  <version>4.0.1</version>
+  ...
+  <version>4.1.0</version>
+  <version>4.1.1</version>
+  <version>4.2.0-M1</version>
+</versions>
+<lastUpdated>20260820133928</lastUpdated>
+
+Reading the two lists together: spring-boot-starter-aop's last-ever release is 4.0.0-M2.
+spring-boot-starter-aspectj's first-ever release is 4.0.0-M3 -- the very next milestone in the
+4.0 line. It then carries through 4.0.0-RC1, RC2, the 4.0.0 GA, every 4.0.x and 4.1.x patch, and
+into the 4.2.0-M1 pre-release. That is a rename at a specific milestone boundary, not two
+unrelated artifacts and not a starter that was dropped with nothing replacing it.
@@ -0,0 +1,35 @@
+Captured 2026-09-18 from repo1.maven.org (Maven Central):
+https://repo1.maven.org/maven2/org/springframework/boot/spring-boot-starter-aspectj/4.1.1/spring-boot-starter-aspectj-4.1.1.pom
+
+<groupId>org.springframework.boot</groupId>
+<artifactId>spring-boot-starter-aspectj</artifactId>
+<version>4.1.1</version>
+<name>spring-boot-starter-aspectj</name>
+<description>Starter for using aspect-oriented programming with AspectJ</description>
+
+<dependencies>
+  <dependency>
+    <groupId>org.springframework.boot</groupId>
+    <artifactId>spring-boot-starter</artifactId>
+    <version>4.1.1</version>
+    <scope>compile</scope>
+  </dependency>
+  <dependency>
+    <groupId>org.springframework</groupId>
+    <artifactId>spring-aop</artifactId>
+    <version>7.0.9</version>
+    <scope>compile</scope>
+  </dependency>
+  <dependency>
+    <groupId>org.aspectj</groupId>
+    <artifactId>aspectjweaver</artifactId>
+    <version>1.9.25.1</version>
+    <scope>compile</scope>
+  </dependency>
+</dependencies>
+
+The renamed starter's own POM declares exactly spring-aop + aspectjweaver as compile
+dependencies -- the same two jars this module's own pom.xml already lists as the reason it
+depends on spring-boot-starter-aspectj. There is no missing third piece and no behavioural
+difference from assembling the two jars by hand; the starter just does it for you, correctly
+versioned, in one line.
@@ -48,7 +48,10 @@
    </dependency>

    <!-- Resilience4j: annotations are woven by its own aspects, so AspectJ must be present.
-         Boot 4 renamed spring-boot-starter-aop to spring-boot-starter-aspectj. -->
+         Boot 4 renamed spring-boot-starter-aop to spring-boot-starter-aspectj (confirmed against
+         Maven Central's maven-metadata.xml for both artifact IDs and the renamed starter's own
+         published POM, which depends on exactly spring-aop + aspectjweaver, the two jars this
+         file used to add by hand before that was verified). See docs/08-starter-aop-renamed-to-starter-aspectj.md. -->
    <dependency>
      <groupId>io.github.resilience4j</groupId>
      <artifactId>resilience4j-spring-boot4</artifactId>
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# Reproduces, and captures, the real build error from adding spring-boot-starter-aop on
+# Spring Boot 4.1 -- the dependency every pre-Boot-4 Resilience4j / AOP guide tells you to add.
+# See docs/08-starter-aop-renamed-to-starter-aspectj.md.
+set -uo pipefail
+cd "$(dirname "$0")/../broken-example"
+mvn -B -q compile 2>&1 | grep -v '^Picked up\|^WARNING' > ../docs/output/00a-starter-aop-build-error.txt
+echo "captured to docs/output/00a-starter-aop-build-error.txt:"
+cat ../docs/output/00a-starter-aop-build-error.txt