证明

public interface  {
    public void test();
}

public class SingletonServiceImpl implements  {
    public static int count = 0;
    /*构造函数 若非单例则count会一直 +1*/
    public SingletonServiceImpl(){
        count++;
    }
    @Override
    public void test() {
        System.out.println(this);
        System.out.println(count);
    }
}