public ThreadGroupReferenceProxyImpl threadGroupProxy() {
    DebuggerManagerThreadImpl.assertIsManagerThread();
    checkValid();
    if (myThreadGroupProxy == null) {
      ThreadGroupReference threadGroupRef;
      try {
        threadGroupRef = getThreadReference().threadGroup();
      }
      catch (ObjectCollectedException ignored) {
        threadGroupRef = null;
      }
      myThreadGroupProxy = getVirtualMachineProxy().getThreadGroupReferenceProxy(threadGroupRef);
    }
    return myThreadGroupProxy;
  }
public ThreadGroupReferenceProxyImpl threadGroupProxy()