Java的并发修改异常错误 [英] Java Concurrent Modification Exception Error

问题描述

林与一些code玩弄我的大学课程，并从

Im playing around with some code for my college course and changed a method from

public boolean removeStudent(String studentName)
{
    int index = 0;
    for (Student student : students)
    {
        if (studentName.equalsIgnoreCasee(student.getName()))
        {
            students.remove(index);
            return true;
        }
        index++;
    }
    return false;
}

要：

public void removeStudent(String studentName) throws StudentNotFoundException
{
    int index = 0;
    for (Student student : students)
    {
        if (studentName.equalsIgnoreCase(student.getName()))
        {
            students.remove(index);
        }
        index++;
    }
    throw new  StudentNotFoundException( "No such student " + studentName);
}

但是，新方法不断给并发修改错误。我怎样才能避开这个和它为什么发生？

But the new method keeps giving a Concurrent Modification error. How can I get round this and why is it happening?

推荐答案

它，因为你继续履行后遍历列表删除（）。你正在阅读，并在同一时间，它打破了迭代器的foreach循环底层的合同写到列表中。

Its because you continue traversing the list after performing remove(). You're reading and writing to the list at the same time, which breaks the contract of the iterator underlying the foreach loop.

尝试使用 Iterator.remove（） ...

for(Iterator<Student> iter = students.iterator(); iter.hasNext(); ) {
    Student student = iter.next();
    if(studentName.equalsIgnoreCasee(student.getName()) {
        iter.remove();
    }
}

这篇关于Java的并发修改异常错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！