Summary

• Fixes #3931: with @Mapper(mappingControl = DeepClone.class), java.util.Date fields were assigned by reference (setDate(source.getDate())) instead of being cloned.
• Root cause: when DIRECT is disabled, types from the java package are still treated as always-direct. That is correct for immutable types like String, but wrong for mutable Date / Calendar.
• Processor-only fix in MappingResolverImpl: exclude java.util.Date and java.util.Calendar from the always-direct rule when DIRECT is off, and emit an inline clone:
  • Date → new Date(source.getTime())
  • Calendar → ((Calendar) source.clone())
• Default mappers (with DIRECT enabled) are unchanged and still copy the reference.
• No public API changes.

Generated code (after)

if ( source.getDate() != null ) {
    beanA.setDate( new Date( source.getDate().getTime() ) );
}
if ( source.getCalendar() != null ) {
    beanA.setCalendar( ((Calendar) source.getCalendar().clone()) );
}

Test plan

• Issue3931Test — Date/Calendar independence under @DeepClone, null handling
• MappingControlTest — existing deep-clone / mapping-control behaviour
• DateConversionTest — normal Date conversion paths still pass