java - 创建子类对象时如何调用抽象类构造函数？

Question

// how is it call abstract class constructor when i create subclass object ?
abstract class D {
    D() {
        System.out.println("called abstract class D constructor");//print
    }
}
public class DemoAbs extends D {
    DemoAbs() {
        System.out.println("called DemoAbs class constructor");
    }
    // how is it call abstract class constructor when i create subclass object ?
    public static void main(String[] args) {
        DemoAbs d=new DemoAbs();
    }
}

Answer 1

这称为构造函数链接:

构造函数中的第一行是 super()除非你明确调用this()或this(<with args>)或super(<with args>)

您应该经历:

Constructor Chaining in Java

Java Constructor Chaining