案例

package student;
public class Exercise01 {
    public static void main(String[] args) {
        B b = new B();//a , b name, b
    }
}
class A {
    A() {
        System.out.println("a");
    }
    A(String name) {
        System.out.println("a name");
    }
}
class B extends A {
    B() {//有this()就不会调用有super()
        this("abc");
        System.out.println("b");
    }
    B(String name) {
        //默认有 super();
        System.out.println("b name");
    }
}

package student;
public class Exercise02 {
    public static void main(String[] args) {
        C c = new C();
    }
}
class A {//A类
    public A() {
        System.out.println("我是A类");
    }
}
class B extends A { //B类,继承A类        //main方法中： C c =new C(); 输出么内容? 3min
    public B() {
        System.out.println("我是B类的无参构造");
    }
    public B(String name) {//默认调用super()
        System.out.println(name + ":我是B类的有参构造");
    }
}
class C extends B {   //C类，继承 B类
    public C() {
        this("hello");
        System.out.println("我是c类的无参构造");
    }
    public C(String name) {
        super("wty");
        System.out.println("我是c类的有参构造");
    }
}