Java 另一道构造器与构造器重载的题目

public class ConstructorTest2 {
    public static void main(String[] args) {
        new B("test");
    }
}

class B extends A {
    public B(String s) {
        System.out.println(s);
    }

    public B(String s1, String s2) {
        this(s1 + s2 + "3");
    }

    public B() {
        this("4");
    }
}

class A {
    public A(String s) {
        System.out.println(s);
    }

    public A(String s1, String s2) {
        this(s1 + s2);
    }

    public A() {
        this("1", "2");
    }
}

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test