code: @Nonnull
    public EChange removeAll ()
    {
      EChange ret = EChange.UNCHANGED;
      m_aRWLock.writeLock ().lock ();
      try
      {
        if (m_aMap.isNotEmpty ())
        {
          ret = EChange.CHANGED;
          for (final IValidationExecutorSet aVES : m_aMap.values ())
            if (aVES instanceof ValidationExecutorSet)
              ((ValidationExecutorSet) aVES).removeAllExecutors ();
          m_aMap.clear ();
        }
      }
      finally
      {
        m_aRWLock.writeLock ().unlock ();
      }
      return ret;
    }
docs: This is a cleanup method that frees all resources when they are no longer
  needed. This may be helpful because some {@link IValidationExecutor}
  implementations contained in the {@link IValidationExecutorSet} contained
  in this registry might have strong references to {@link ClassLoader}
  instances. By calling this method, you can clear the contained map and
  invoke {@link ValidationExecutorSet#removeAllExecutors()} if applicable.
  
  @return {@link EChange}