JPA Maven setup in docs no longer works on JDK 23+; need update to annotationProcessorPaths

[q975144677]

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Is your feature request related to a problem? Please describe.

Yes — the documented JPA setup no longer generates Q classes on modern JDKs, which makes the official documentation
actively misleading for new users.

The JPA tutorial at https://openfeign.github.io/querydsl/tutorials/jpa/querydsl instructs users to configure the
annotation processor via the maven-compiler-plugin's own <dependencies> block:

<plugin>
  <artifactId>maven-compiler-plugin</artifactId>
  <configuration>
    <generatedSourcesDirectory>target/generated-sources/java</generatedSourcesDirectory>
  </configuration>
  <dependencies>
    <dependency>
      <groupId>io.github.openfeign.querydsl</groupId>
      <artifactId>querydsl-apt</artifactId>
      <version>7.1</version>
      <classifier>jpa</classifier>
    </dependency>
    <dependency>
      <groupId>jakarta.persistence</groupId>
      <artifactId>jakarta.persistence-api</artifactId>
      <version>3.1.0</version>
    </dependency>
  </dependencies>
</plugin>

This approach relies on implicit annotation processing, where javac auto-discovers processors on the classpath.
Implicit annotation processing was deprecated in JDK 21 and fully removed in JDK 23. On JDK 23+ (I'm on JDK 25),
this configuration is silently ignored — no Q classes are produced.

Meanwhile, the referenced Examples instead put querydsl-apt as a project-level dependency:

<dependency>
  <groupId>io.github.openfeign.querydsl</groupId>
  <artifactId>querydsl-jpa</artifactId>
  <version>7.5</version>
</dependency>
<dependency>
  <groupId>io.github.openfeign.querydsl</groupId>
  <artifactId>querydsl-apt</artifactId>
  <version>7.5</version>
  <classifier>jpa</classifier>
</dependency>

But Maven does not recognize querydsl-apt as an annotation processor from a plain project dependency on JDK 23+.
Here is the confusing symptom: IntelliJ IDEA's "Build" generates Q classes correctly (IDEA runs its own
annotation-processing pipeline and picks up processors from the module classpath), but after mvn clean, neither mvn compile, mvn install, nor mvn package produces Q classes. This divergence between IDE builds and Maven builds
is very easy to mistake for a user error.

Describe the solution you'd like

Please update the JPA tutorial documentation to use the modern, explicit annotationProcessorPaths configuration,
which works reliably across JDK versions (including 23+):

<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-compiler-plugin</artifactId>
      <version>3.13.0</version>
      <configuration>
        <proc>full</proc>
        <generatedSourcesDirectory>${project.build.directory}/generated-sources/java</generatedSourcesDirectory>
        <annotationProcessorPaths>
          <path>
            <groupId>io.github.openfeign.querydsl</groupId>
            <artifactId>querydsl-apt</artifactId>
            <version>7.5</version>
            <classifier>jpa</classifier>
          </path>
          <path>
            <groupId>jakarta.persistence</groupId>
            <artifactId>jakarta.persistence-api</artifactId>
            <version>3.1.0</version>
          </path>
        </annotationProcessorPaths>
      </configuration>
    </plugin>
  </plugins>
</build>

Two details matter here, and both are worth documenting explicitly:

1. <proc>full</proc> — with implicit annotation processing removed on JDK 23+, this explicitly re-enables
   processing.
2. jakarta.persistence-api must be listed inside annotationProcessorPaths — annotationProcessorPaths runs
   the processor on an isolated classpath containing only the listed paths, so without JPA annotations the processor
   cannot inspect @Entity and silently produces nothing.

Describe alternatives you've considered

• Keeping the current project-level querydsl-apt dependency: works in the IDE but not in Maven on JDK 23+; also
  leaks the processor to downstream consumers. Not a fix.
• Sticking with the documented plugin <dependencies> block: only works on JDK 21 and earlier. Not a fix.
• annotationProcessorPaths (chosen): the standard, recommended approach; explicit, isolated, and version-robust.

Additional context

• JDK: 25 (behavior starts at JDK 23; deprecated in 21).
• Maven: mvn compile / install / package all fail to generate Q classes.
• I am happy to submit a PR to update the tutorial and any Examples docs that show the legacy configuration.