ProcessorTests are currently unable to reload Mapper implementation class #4132

Expected behavior

When a Mapper implementation is loaded in a test like

@ProcessorTest
void someTest() {
    MyMapper mapper = Mappers.getMapper( MyMapper.class );
}

the loaded Mapper should be the one generated by the test. For example the one generated by Eclipse or JDK compiler.

Actual behavior

Currently a Mapper implementation is only loaded once from whatever test run loads it first.
This a limitation of the used class loading.

Steps to reproduce the problem

@ProcessorTest
void someTest() {
    MyMapper mapper = Mappers.getMapper( MyMapper.class );
    System.out.println( mapper.getClass().getProtectionDomain().getCodeSource().getLocation() );
}

You will see that the source code location does not change

MapStruct Version

All versions