简单且线程安全的两个单例模式java程序

/**
*具体说明见  http://www.cnblogs.com/coffee/archive/2011/12/05/inside-java-singleton.html
*/


package com.work.pattern;



public class Singleton2 {


    private static  Singleton2 instance = new Singleton2();

    private Singleton2(){

        

    }

    public static Singleton2 getInstance(){

        return instance;

    }

}

package com.work.pattern;



/**

 * 单例模式创新！google的ioc作者写的。只有在调用的时候才会初始化！而且线程安全

 * 超级牛！


 *

 */

public class Singleton {



    static class SingletonHolder {

        static Singleton instance = new Singleton();

    }



    public static Singleton getInstance() {

        return SingletonHolder.instance;

    }



}