Why parameter names is not being kept when annotation processor is run by JDT ?

[cvgaviao]

Hello, I'm using Eclipse 202406 with jdk-21 and m2e.

My project uses maven and we use annotation processor to generate code for Mapstruct and Immutables.
It have the following settings:

eclipse.preferences.version=1
org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
org.eclipse.jdt.core.compiler.codegen.methodParameters=generate
org.eclipse.jdt.core.compiler.codegen.targetPlatform=21
org.eclipse.jdt.core.compiler.codegen.unusedLocal=optimize out
org.eclipse.jdt.core.compiler.compliance=21
org.eclipse.jdt.core.compiler.debug.lineNumber=generate
org.eclipse.jdt.core.compiler.debug.localVariable=generate
org.eclipse.jdt.core.compiler.debug.sourceFile=generate
org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
org.eclipse.jdt.core.compiler.problem.forbiddenReference=warning
org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
org.eclipse.jdt.core.compiler.processAnnotations=enabled
org.eclipse.jdt.core.compiler.release=enabled
org.eclipse.jdt.core.compiler.source=21

But even with this I'm getting different behavior than the one code generated by jdk-21.

Below is the code generated by JDT:

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2024-09-05T08:18:58+0100",
    comments = "version: 1.6.0, compiler: Eclipse JDT (IDE) 3.38.0.v20240524-2033, environment: Java 21 (Oracle Corporation)"
)
@ApplicationScoped
public class BusinessUnitMapperImpl implements BusinessUnitMapper {

    @Override
    public UserOnBusinessUnitDto mapJoinDto(BusinessUnitsUsers **arg0**) {
        if ( arg0 == null ) {
            return null;
        }

and this is the code generated by JDK:

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2024-09-05T08:29:11+0100",
    comments = "version: 1.6.0, compiler: javac, environment: Java 21 (Oracle Corporation)"
)
@ApplicationScoped
public class BusinessUnitMapperImpl implements BusinessUnitMapper {

    @Override
    public UserOnBusinessUnitDto mapJoinDto(BusinessUnitsUsers **pJoinEntity**) {
        if ( pJoinEntity == null ) {
            return null;
        }

Note the arg0 vs pJoinEntity parameter names ?

Am I missing something ?