java-类的加载机制demo（一）

package com.test.testClass;

public class Test {

    private static Test instance = new Test();
    private static int x = 0;
    private static int y;


    private Test() {
        x++;
        y++;
    }

    private static Test getInstance() {
        return instance;
    }

    public static void main(String[] args) {
        Test test = Test.getInstance();
        System.out.println(Test.x);
        System.out.println(Test.y);
    }
}

---

package com.test.testClass;

public class Test {

    private static int x = 0;
    private static int y;
    private static Test instance = new Test();


    private Test() {
        x++;
        y++;
    }

    private static Test getInstance() {
        return instance;
    }

    public static void main(String[] args) {
        Test test = Test.getInstance();
        System.out.println(Test.x);
        System.out.println(Test.y);
    }
}

---

上下两个程序输出：

上：0 ，1

下：1， 1

原理是：类的加载机制（加载，连接（验证，准备，解析），初始化）这个过程。