Question

这道Java题怎么做？

创建类A1，实现构造方法中输出This is A;创建A1的子类B1，实现构造方法中输出This is B;创建B1的子类C1，实现构造方法中输出This is C。

Answer 1

public class A1 {
public A1() {
System.out.println("This is A");
}

public static void main(String[] args) {
A1 c1 = new C1();
}
}

class B1 extends A1{
public B1() {
System.out.println("This is B");
}
}

class C1 extends B1 {
public C1() {
System.out.println("This is C");
}
}