code: static void unregister(Object value) {
          if (value != null) {
              Map<Object, Object> m = getRegistry();
              if (m != null) {
                  m.remove(value);
                  if (m.isEmpty()) {
                      REGISTRY.remove();
                  }
              }
          }
      }
docs: <p>
  Unregisters the given object.
  </p>
  <p/>
  <p>
  Used by the reflection methods to avoid infinite loops.
  </p>
  
  @param value The object to unregister.