java.util.ConcurrentModificationException 异常

原码：

public List findGroupsByCid(String cid) throws Exception {
  List groupList = new ArrayList();
  groupList = gdao.findGroupsByCid(cid);

  //count account in this group's number
  Iterator it = groupList.iterator();
  while (it.hasNext()) {
   Group group = (Group) it.next();
   List aglist=new ArrayList();
   aglist=agdao.findByGid(group.getGid());
   Iterator it1=aglist.iterator();
   while (it1.hasNext()) {
    Agmapping agmapping = (Agmapping) it1.next();
    Account account=adao.findByAid(agmapping.getAid());
    if(null==account||null==account.getAid()||"".equals(account.getAid())){
     aglist.remove(agmapping);
    }
   }   
   group.setPcount(aglist.size());
  }
  return groupList;
 }

 出现java.util.ConcurrentModificationException 异常，解决办法：

将红色区域的代码换成：it1.remove();

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