java.util.ConcurrentModificationException 异常

使用 jbpm时，查找需要singal的task时代码如下， 

    Iterator it1=collect.iterator(); 
  while(it1.hasNext()){
     TaskInstance taskInstance=(TaskInstance)it1.next(); //在该行处报异常。
     Set actorSet = taskInstance.getPooledActors();
     Iterator iterator = actorSet.iterator();
     while(iterator.hasNext()){
      PooledActor poolAct = (PooledActor)iterator.next();
      if((""+userId).equals(poolAct.getActorId())
       &&!taskInstance.hasEnded() ){
       Set set = taskInstance.getToken().getNode().getArrivingTransitions();
       taskInstance.end();
      }
     }
    }

在网上查找到，

一个Collection进行遍历(iteration)同时,对这个Collection里面的元素(element)进行做修改时,就会抛出java.util.ConcurrentModificationException.

故将代码修改为如下：

//Iterator it1=collect.iterator(); //修改1
    Object[] objs = collect.toArray();
    for(int j=0;j<objs.length;j++){
//    while(it1.hasNext()){ //修改2
     TaskInstance taskInstance=(TaskInstance)objs[j];
     Set actorSet = taskInstance.getPooledActors();
     Iterator iterator = actorSet.iterator();
     while(iterator.hasNext()){
      PooledActor poolAct = (PooledActor)iterator.next();
      if((""+userId).equals(poolAct.getActorId())
       &&!taskInstance.hasEnded() ){
       Set set = taskInstance.getToken().getNode().getArrivingTransitions();
       taskInstance.end();
      }
     }
    }
经测试通过。