public class Test { public static Test t1 = new Test(); { System.out.println("blockA"); } static { System.out.println("blockB"); } public static void main(String[] args) { Test t2 = new Test(); } }
public class Test { public static Test t1 = new Test(); { System.out.println("blockA"); } static { System.out.println("blockB"); } public static void main(String[] args) { Test t2 = new Test(); } }
blockAblockBblockA
blockAblockAblockB
blockBblockBblockA
blockBblockAblockB
blockA blockB blockA
public class Test { public static Test t1 = new Test();//静态变量 //构造块 { System.out.println("blockA"); } //静态块 static { System.out.println("blockB"); } public static void main(String[] args) { Test t2 = new Test(); } }静态域:用staitc声明,jvm加载类时执行,仅执行一次
答案是 blockAblockBblockA
首先区别<clinit>是类初始化,<init>是实例初始化
类装载准备阶段->类初始化clinit阶段
类装载准备阶段:变量赋系统要求的初始值(0或者null等),final变量会在此时赋用户定义的初始值
类初始化<clinit>过程:
Step1 编译器收集t1的赋值动作,static语句块,main方法语句块
Step2 执行收集好的语句块:
Step2.1 执行t1 = new Test,发现clinit过程已经调用,于是可以开始触发init过程,执行成员变量的初始化(此处没有),以及非静态代码块,输出blockA,最后调用构造函数(此处没有)
Step2.2 按照顺序,执行static语句块,输出blockB
Step2.3 按照顺序,执行main方法语句块,执行t2 = new Test,触发init方法,执行非静态代码块,输出blockA
public static Test t1 = new Test();
Test t2 = new Test();