code: @Override
      public void clear() throws CouldNotPerformException {
          lock();
          try {
              pluginPool.beforeClear();
              sandbox.clear();
              entryMap.clear();
              consistent = true;
          } finally {
              unlock();
          }
          notifyObservers();
      }
docs: {@inheritDoc}
  
  @throws CouldNotPerformException {@inheritDoc}