package com.day3;public class SingleTonDemo {   public static void main(String[] args) {       SinleTonThread sinleTonThread=new SinleTonThread();       Thread thread=new Thread(sinleTonThread);       thread.start();       Thread thread2=new Thread(sinleTonThread);       thread2.start();}}class SinleTonThread  implements Runnable{    @Override    public void run() {        SingleTon.getinstance();            }    }class SingleTon{    private static SingleTon singleTon=null;    private SingleTon() {        System.out.println("单例模式");    }    public static SingleTon getinstance(){        if(singleTon==null) {            synchronized (SingleTon.class) {                if(singleTon==null) {                    singleTon=new SingleTon();                }            }            }                        return singleTon;            }}