编写一个Singleton程序(单例)

public class Test {
    private static  Test test = new Test();
    private Test(){}//构造方法私有化
    private static Test test(){
        return test;
    }
    public void run(){
        System.out.println("run");
    }

    public static void main(String[] args) {
        Test s = Test.test();
        s.run();
    }
}