Program: 89918
Project: 89918
Buggy source:
@Override @DB public void processAnswer(VMOperationListener listener,long agentId,long seq,Answer answer){
  UserVmVO vm=listener.getVm();
  VMOperationParam param=listener.getParam();
  AsyncJobManager asyncMgr=getAsyncJobMgr();
  ManagementServer managementServer=asyncMgr.getExecutorContext().getManagementServer();
  String params="String_Node_Str" + vm.getId() + "String_Node_Str"+ vm.getHostName()+ "String_Node_Str"+ vm.getServiceOfferingId()+ "String_Node_Str"+ vm.getTemplateId()+ "String_Node_Str"+ vm.getDataCenterId();
  if (s_logger.isDebugEnabled())   s_logger.debug("String_Node_Str" + vm.getHostId() + "String_Node_Str"+ seq);
  boolean stopped=false;
  if (answer != null && answer.getResult())   stopped=true;
  try {
    if (stopped) {
      asyncMgr.getExecutorContext().getVmMgr().completeStopCommand(param.getUserId(),vm,Event.OperationSucceeded,param.getChildEventId());
      Transaction txn=Transaction.currentTxn();
      txn.start();
      asyncMgr.getExecutorContext().getAccountMgr().decrementResourceCount(vm.getAccountId(),ResourceType.user_vm);
      if (!asyncMgr.getExecutorContext().getItMgr().stateTransitTo(vm,VirtualMachine.Event.DestroyRequested,vm.getHostId())) {
        s_logger.debug("String_Node_Str" + vm.toString());
        txn.rollback();
        asyncMgr.completeAsyncJob(getJob().getId(),AsyncJobResult.STATUS_FAILED,0,"String_Node_Str");
        return;
      }
      asyncMgr.getExecutorContext().getVmMgr().cleanNetworkRules(param.getUserId(),vm.getId());
      List<VolumeVO> volumes=asyncMgr.getExecutorContext().getVolumeDao().findByInstanceAndType(vm.getId(),VolumeType.ROOT);
      for (      VolumeVO volume : volumes) {
        asyncMgr.getExecutorContext().getStorageMgr().destroyVolume(volume);
      }
      volumes=asyncMgr.getExecutorContext().getVolumeDao().findByInstanceAndType(vm.getId(),VolumeType.DATADISK);
      for (      VolumeVO volume : volumes) {
        asyncMgr.getExecutorContext().getVolumeDao().detachVolume(volume.getId());
      }
      txn.commit();
      asyncMgr.completeAsyncJob(getJob().getId(),AsyncJobResult.STATUS_SUCCEEDED,0,"String_Node_Str");
    }
 else {
      asyncMgr.getExecutorContext().getItMgr().stateTransitTo(vm,Event.OperationFailed,vm.getHostId());
      asyncMgr.completeAsyncJob(getJob().getId(),AsyncJobResult.STATUS_FAILED,BaseCmd.INTERNAL_ERROR,"String_Node_Str" + vm.getHostName());
    }
  }
 catch (  Exception e) {
    s_logger.error("String_Node_Str" + e.getMessage(),e);
  }
 finally {
    asyncMgr.releaseSyncSource(this);
  }
}

Fixed version (ground truth):
@Override @DB public void processAnswer(VMOperationListener listener,long agentId,long seq,Answer answer){
  UserVmVO vm=listener.getVm();
  VMOperationParam param=listener.getParam();
  AsyncJobManager asyncMgr=getAsyncJobMgr();
  ManagementServer managementServer=asyncMgr.getExecutorContext().getManagementServer();
  String params="String_Node_Str" + vm.getId() + "String_Node_Str"+ vm.getName()+ "String_Node_Str"+ vm.getServiceOfferingId()+ "String_Node_Str"+ vm.getTemplateId()+ "String_Node_Str"+ vm.getDataCenterId();
  if (s_logger.isDebugEnabled())   s_logger.debug("String_Node_Str" + vm.getHostId() + "String_Node_Str"+ seq);
  boolean stopped=false;
  if (answer != null && answer.getResult())   stopped=true;
  try {
    if (stopped) {
      asyncMgr.getExecutorContext().getVmMgr().completeStopCommand(param.getUserId(),vm,Event.OperationSucceeded,param.getChildEventId());
      Transaction txn=Transaction.currentTxn();
      txn.start();
      asyncMgr.getExecutorContext().getAccountMgr().decrementResourceCount(vm.getAccountId(),ResourceType.user_vm);
      if (!asyncMgr.getExecutorContext().getItMgr().stateTransitTo(vm,VirtualMachine.Event.DestroyRequested,vm.getHostId())) {
        s_logger.debug("String_Node_Str" + vm.toString());
        txn.rollback();
        asyncMgr.completeAsyncJob(getJob().getId(),AsyncJobResult.STATUS_FAILED,0,"String_Node_Str");
        return;
      }
      asyncMgr.getExecutorContext().getVmMgr().cleanNetworkRules(param.getUserId(),vm.getId());
      List<VolumeVO> volumes=asyncMgr.getExecutorContext().getVolumeDao().findByInstanceAndType(vm.getId(),VolumeType.ROOT);
      for (      VolumeVO volume : volumes) {
        asyncMgr.getExecutorContext().getStorageMgr().destroyVolume(volume);
      }
      volumes=asyncMgr.getExecutorContext().getVolumeDao().findByInstanceAndType(vm.getId(),VolumeType.DATADISK);
      for (      VolumeVO volume : volumes) {
        asyncMgr.getExecutorContext().getVolumeDao().detachVolume(volume.getId());
      }
      txn.commit();
      asyncMgr.completeAsyncJob(getJob().getId(),AsyncJobResult.STATUS_SUCCEEDED,0,"String_Node_Str");
    }
 else {
      asyncMgr.getExecutorContext().getItMgr().stateTransitTo(vm,Event.OperationFailed,vm.getHostId());
      asyncMgr.completeAsyncJob(getJob().getId(),AsyncJobResult.STATUS_FAILED,BaseCmd.INTERNAL_ERROR,"String_Node_Str" + vm.getName());
    }
  }
 catch (  Exception e) {
    s_logger.error("String_Node_Str" + e.getMessage(),e);
  }
 finally {
    asyncMgr.releaseSyncSource(this);
  }
}