checkForComodification

//执行这段代码是会抛出异常 ConcurrentModificationException
for (String str : list) {   
    if ("remove".equals(str)) {
        list.remove(str);
    }
}

//具体位置
final void checkForComodification() {  
 	if (modCount != expectedModCount)  
 		throw new ConcurrentModificationException();  
}