code: private final void releaseDTMXRTreeFrags(){
      if(m_DTMXRTreeFrags == null){
        return;
      }
      final Iterator iter = (m_DTMXRTreeFrags.values()).iterator();
      while(iter.hasNext()){
        DTMXRTreeFrag frag = (DTMXRTreeFrag)iter.next();
        frag.destruct();
        iter.remove();
      }
      m_DTMXRTreeFrags = null;
   }
docs: Cleans DTMXRTreeFrag objects by removing references
  to DTM and XPathContext objects.