单例模式

public class Singleton {     private volatile static Singleton uniqueInstance;    private Singleton();public static Singleton getInstance(){   if(uniqueInstance==null){

<span style="white-space:pre"></span>synchronized(Singleton.class){<span style="white-space:pre"></span>if(uniqueInstance== null){

<span style="white-space:pre"></span>uniqueInstance = new Singleton();

}

{

}

return uniqueInstance;

}    }}