java - 执行从抽象类派生的子类的静态 block

Question

public class Test15 {
    public static void main(String[] args) {
        System.out.println(B.x);
    }
}

abstract class A { 
    static int x=99;

    A() {
        System.out.println("A DC");
    }

    static {
        System.out.println("A SB");
    }
}

class B extends A {
    static {
        System.out.println("B Sb");
    }
}

为什么在上面的程序中子类静态 block 没有被执行？

Answer 1

x 是 A 类的 static 变量，因此即使您通过 B.x 访问它，也有无需初始化类 B。因此，类 B 的 static 初始化程序不会被执行。

这是相关的JLS 12.4.1 quote :

A reference to a static field (§8.3.1.1) causes initialization of only the class or interface that actually declares it, even though it might be referred to through the name of a subclass, a subinterface, or a class that implements an interface.