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Maven JPA integration: processor not found

Maven JPA integration: processor not found

Personal Project:
I am new to Maven and have spent a few weeks troubleshooting pom errors with chatGPT. Tutorials are hard to come by online, because annotation-processing in Java is more complicated than the sources I've found. Issue in summary: my annotation processor "cannot be found" but everything \~looks okay. I need help spotting the issue in my Pom; Thank you in advance!

Background: In Eclipse IDE, I created a new Maven project with the quickstart-architype resulting in a project with this structure:


`Project:` 
<br>`____pom.xml`
<br>`____src / main / java:`
<br>`________com.folder.Project:`
<br>`____________App.java`

<i><b>There isn't a META-INF directory in the Project hierarchy;</b> it does not get generated when I create Maven projects, but it should not be the issue.</i>

I also some files/ directories to com.folder.Project, resulting in:

`com.folder.Project:`
<br>`____App.java`
<br>`____archive:`
<br>`________Annotation.java`
<br>`____processors:`
<br>`________AnnotationProcessor.java`

<i>This is a new project, and there are not any added files outside of what I have mentioned. These added files even have the same name in my setup; I've set it up like this, purely to troubleshoot + learn how to create annotation processors in java.</i>

<b>Issue:
In the terminal, when I run "mvn compile -X" or other similar commands, I get an Error:
diagnostic: error: Annotation processor 'com.folder.Project.processors.AnnotationProcessor' not found.</b>

pom.xml:  
```<groupid>com.folder</groupid>
<artifactid>Project</artifactid>
<version>2024</version>
<packaging>jar</packaging>
<name>Project</name>
<url>http://maven.apache.org</url>
<dependencies>
    <dependency>
        <groupid>junit</groupid>
        <artifactid>junit</artifactid>
        <version>3.8.1</version>
        <scope>test
    </dependency>
    <dependency>
         <groupid>org.bsc.maven</groupid>
         <artifactid>maven-processor-compiler</artifactid>
         <version>5.0-jdk8</version>
     </dependency>
     <dependency>
         <groupid>org.bsc.maven</groupid>
         <artifactid>maven-processor-plugin</artifactid>
         <version>5.0-jdk8-rc3</version>
     </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupid>org.apache.maven.plugins</groupid>
            <artifactid>maven-compiler-plugin</artifactid>
            <version>3.11.0</version>
        </plugin>
        <plugin>
            <groupid>org.bsc.maven</groupid>
            <artifactid>maven-processor-plugin</artifactid>
            <version>5.0-jdk8-rc3</version>
            <executions>
                <execution>
                    <id>process</id>
                    <goals>
                        <goal>process
                    </goals>
                    <phase>generate-sources</phase>
                        <configuration>
                            <processors>
                                <processor>com.open.Engine.processors.AnnotationProcessor</processor>
                            </processors>
                        </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>
```

The mistake is probably in my pom. 
<br><i>I had to retype <tag>'s and </tag>'s, so ignore spelling errors related to those; in the XML view on Eclipse, each tag gives a meaningful description (versus, if a tag was spelled incorrectly or misplaced, it might not).</i>

Here are the simple classes I made for testing:

Annotation.java:
```package com.folder.Project.archive;
// import from java.lang.annotation.Documented;
@Documented
public @interface Annotation { /*does nothing*/ }
```

AnnotationProcessor.java:
```package com.folder.Project.processors;
// imports from javax, and java.util.Set;
@SupportedAnnotationTypes( "com.folder.Project.archive.Annotation" ) // I'm not sure if this matches
public class AnnotationProcessor extends AbstractProcessor {
    @Override public boolean process ( ... ) // Set and RoundElement inputs
    {
        processingEnv.getMessager().printMessage( Diagnostic.Kind.ERROR, "Error" );
        return false; // so it should fail every time (which lets me know if it works)
    }
}
```


App.java:
```import com.folder.Project.archive.Annotation;
... main( String[] args ) {
    @Annotation int x = 1;
    System.out.println( "finished main" );
}
```


The code is written so I can verify an annotation processor is executed at all.

--------

A few notes:
<i>
* diagnostic: error: Annotation processor 'com.folder.Project.processors.AnnotationProcessor' not found; is the 1st error to appear after running mvn compile.

* "mvn clean compile -X" doesn't elaborate on the error: Build Fail / could Not Execute / could not achieve goal.

* I run "Build Project", "Build All", and "Run" after every significant change to pom.xml.

* \<annotationprocessingpaths\>, from an alternative solution, was not a recognized tag in my pom dependency hierarchy (alternative solutions failed too).

* I have confirmed the spelling is correct in the files, with the correct filenames as well. If you see any spelling errors above, it's probably because I mistyped them into the question-forum text editor.</i>

------

I'm trying to build annotation processors in Java; I think it has potential for lots of future projects. I understand it's a little niche, but also think it is probably important to know / be able to use effectively.

What steps should I take to get everything running normally, for annotation processing? What errors have I made?

<b>Thank you for your time</b>

- Tyler Bakeman