java中的单例模式，相对于new而言，可以提升性能

package com.chinasoft.util;


public class Singleton {
private static Singleton singleton;


private Singleton() {


}


public static Singleton getInstance() {
if (singleton == null) {
singleton = new Singleton();
}
return singleton;
}
public static void main(String[] args) {
Singleton s1=Singleton.getInstance();
Singleton s2=Singleton.getInstance();
System.out.println(s1.equals(s2));
}

}