java - java中不可修改的列表

Question

如果我尝试修改java中设置为不可修改的列表，我对实际会发生什么感到困惑，我对Java相对较新，从我可以找到的其他人问过类似的问题来看它仍然可以修改吗？如果是的话，这是为什么？

谢谢。

Answer 1

直接来自JavaDoc :

Returns an unmodifiable view of the specified list. This method allows modules to provide users with "read-only" access to internal lists. Query operations on the returned list "read through" to the specified list, and attempts to modify the returned list, whether direct or via its iterator, result in an UnsupportedOperationException.

因此它将抛出UnsupportedOperationException。

或者从源代码:

    public E set(int index, E element) {
        throw new UnsupportedOperationException();
    }
    public void add(int index, E element) {
        throw new UnsupportedOperationException();
    }
    public E remove(int index) {
        throw new UnsupportedOperationException();
    }
    //etc...