JavaSE 单例

public class Singleton {
    private final static Singleton INSTANCE = new Singleton();
    private Singleton(){
    }
    public static Singleton getInstance() {
        return INSTANCE;
    }
}
public class SingletonTest {
        public static void main(String[] args) {
            Singleton st1 = Singleton.getInstance();
            Singleton st2 = Singleton.getInstance();
            System.out.println(st1==st2);
        }
}