Scope of private variables in an inner class?

问题:

What is the scope of variables that are declared as private in an inner class? For example what would be the scope of key variable in th code given below.

package redblacktrees;

public class RedBlackTrees<Key extends Comparable <Key>,Val> {

    private Node root;

    private class Node
    {
        private Key key;  //what is thescope of this variable
        private Val val;
        private Node left, right;

    }

    public Val get(Key key)
    {
        Node x = root;
        while(x != null)
        {
            int cmp = key.compareTo(x.key);
            if(cmp < 0)
                x = x.left;
            else if(cmp > 0)
                x = x.right;
            else
                return x.val;
        }

        return null;

    }
}

回答1:

The scope is between the { and } of Node however it is accessible to any code under RedBlackTrees provided you give an explicit path.

BTW When you access private members this way, the javac compiler has to add accessor methods which don't slow down the code that much but can give confusing stack traces. For simplicity I would make the members "package local".