Java 构造函数及类成员变量初始化顺序

父类静态成员变量 -> 本类静态变量 -> 父类非静态变量 -> 父类构造函数 -> 本类非静态变量 ->本类构造函数

public class Main {

    public static void main(String[] args) {
        TestClass tc = new TestClass();
    }

    private static class Base {
        public Base(String id) {
            System.out.println("Base initialized :"+id);
        }
    }
    private static class Parent {
        Base b2 = new Base("b2");
        static Base b4 = new Base("b4");
        public Parent() {
            System.out.println("Parent initialized.");
            testSync();
        }
        public void testSync() {
            System.out.println("Parent testSync.");
        }
    }
    //测试java 构造函数和类变量的初始化流程：
    //static成员变量会最先被初始化
    //然后是父类构造函数
    //然后是非static成员变量
    //然后是本类构造函数
    private static class TestClass extends Parent{
        private final static Base b = new Base("b1");
        private final Base b3 = new Base("b3");
        public TestClass() {
            //super();
            synchronized(b3) {
                System.out.println("TestClass initialized.");
            }
        }
        @Override
        public void testSync() {
            synchronized(b) { //crash on synchronized(b3)
                System.out.println("TestClass testSync.");
            }
        }
    }
}