获取并发修改异常只是为了尝试读取ArrayList的元素

Question

我知道当我尝试修改或从列表中删除时,我会得到此异常,但只是为了从中读取？这里有什么解决方案？

public boolean recieveHello(Neighbor N, HelloMsg H) {
        Iterator<Neighbor> I = NTable.iterator();
        Iterator<Neighbor> J = NTable.iterator();
        if(!J.hasNext()) {
            this.NTable.add(N);
        }

        while(I.hasNext()) {
            if(I.next().nid == N.getnid()) {  /*EXCEPTION IS HERE*/
                //case where the node is already present in the NTable
            }
            else {
                N.setnhrc(0);  
                this.NTable.add(N);
                //case where the node is to be added to the NTable
            }
        }
        return true;
    }

顺便说一句,我必须提到NTable是一个arrayList,并且是类的成员,其方法是这样的

编辑

我用::解决了这个问题

public boolean recieveHello(Neighbor N, HelloMsg H) {
        Iterator<Neighbor> I = NTable.iterator();
        Iterator<Neighbor> J = NTable.iterator();
        if(!J.hasNext()) {
            this.NTable.add(N);
        }
        boolean flag = false;
        for (int i=0; i<NTable.size(); i++) {
            if(NTable.get(i).nid == N.getnid()) {
                //case where the node is already present in the NTable
            }
            else {
                flag = true;
                N.setnhrc(0);  
                this.NTable.add(N);
                //case where the node is to be added to the NTable
            }
        }
        if(flag == true) {

        }
        return true;
    }

Answer 1

那么当你说时,你正在改变列表的大小,同时迭代它

  this.NTable.add(N);

因此,请在单独的列表中跟踪要添加的内容,然后在第一次迭代后附加项目.