Java单例模式之饱汉式和饥汉式写法

Java中单例模式有两种比较通俗易懂的写法,单例模式是笔试的常见题目,可以看看.
饱汉式:

public class SingleTon {    private SingleTon(){}    private final static SingleTon instance = new SingleTon();    public static SingleTon getInstance () {        return instance;    }}

饿汉式:

public class SingleTon{    //创建构造方法    private SingleTon(){}    //创建实例对象    private static instance = null;    public static synchronized SingleTon getInstance (){        if(instance == null){            instance = new SingleTon();            return instance;        }    }}