Singleton 单列模式的java实现(转)
Singleton 单列模式在实际应用的机会很多。

最近刚好碰到，所以顺便总结了下。

一、最常见的实现如下：（不支持多线程）

public class Singleton {// Private constructor prevents instantiation from other classesprivate Singleton() {}/*** SingletonHolder is loaded on the first execution of Singleton.getInstance()* or the first access to SingletonHolder.INSTANCE, not before.*/private static class SingletonHolder {private static final Singleton INSTANCE = new Singleton();}public static Singleton getInstance() {return SingletonHolder.INSTANCE;}}