undefined.java

来自「javascript语言的解释器源码」· Java 代码 · 共 23 行

package org.mozilla.javascript;

import java.io.Serializable;

/**
 * This class implements the Undefined value in JavaScript.
 */
public class Undefined implements Serializable
{
    static final long serialVersionUID = 9195680630202616767L;

    public static final Object instance = new Undefined();

    private Undefined()
    {
    }

    public Object readResolve()
    {
        return instance;
    }
}