设计模式 之 单例模式

package com.test.pattern;

class Singleton {
    private static Singleton singleton;
    private Singleton(){
        System.out.println("hello I‘m singleton "+this.hashCode());
    }
    public static Singleton getSingleton() {
        if(singleton == null)
            singleton = new Singleton();
        return singleton;
    }
}
public class SingletonTest {
    public static void main(String[] args) {
        Singleton.getSingleton();
        Singleton.getSingleton();
        Singleton.getSingleton();
    }
}