code: TypeConverter getDeclaredTypeConverter(MapOnly mapOnly, TypeConverter fallback) {
          if (null != mapOnly) {
              TypeConverter typeConverter = getDeclaredTypeConverter(
                      mapOnly.typeConverterClass().getName(), mapOnly.typeConverter());
              if (null != typeConverter) {
                  return typeConverter;
              }
          }
          return fallback;
      }
docs: Determine type converter for a @MapOnly annotation (falling back to @MappedBy type converter.
  
  @param mapOnly MapOnly annotation
  @param fallback type converter from MappedBy annotation
  @return type converter with highest precedence