code: @Override
      final public void cleanup() throws ResourceException {
  
          if (TraceComponent.isAnyTracingEnabled() && TRACE.isEntryEnabled()) {
              SibTr.entry(this, TRACE, "cleanup");
          }
  
          // Invalidate all of the sessions
  
          for (final Iterator iterator = _sessions.iterator(); iterator.hasNext();) {
              final Object object = iterator.next();
              if (object instanceof JmsJcaSessionImpl) {
                  ((JmsJcaSessionImpl) object).invalidate();
              }
          }
          _sessions.clear();
  
          if (TraceComponent.isAnyTracingEnabled() && TRACE.isEntryEnabled()) {
              SibTr.exit(this, TRACE, "cleanup");
          }
  
      }
docs: Cleans up this managed connection so that it can be returned to the free
  pool. Any sessions that are still associated should be invalidated.
  
  @throws ResourceException
  generic exception