code: private boolean isIgnoredType(Class<?> pReturnType) {
          for (Class<?> type : IGNORED_RETURN_TYPES) {
              if (type.isAssignableFrom(pReturnType)) {
                  return true;
              }
          }
          return false;
      }
docs: as safety net. I messed up my complete local Maven repository only be serializing a Jetty ServletContext