public class A extends Base {
    double height = 6.0;

    public static void main(String args[]) {
        System.out.println("hello");
        A a = new A();
    }

    public A() {
        super();    // [The compiler does this if you delete this line.]
        System.out.println("in A() constructor");
        showAttributes();
        System.out.println("end of A() constructor");
    }

    protected void showAttributes() {
        System.out.println("A.showAttributes() : " + getClass().getSimpleName() + "(height=" + height + ")");
        super.showAttributes();     // [Added this line]
    }
}

class Base {
    double weight = 150.0;

    protected Base() {
        System.out.println("in B() constructor");
        showAttributes();
        System.out.println("end of B() constructor");
    }

    protected void showAttributes() {
        System.out.println("B.showAttributes() : " + getClass().getSimpleName() + "(weight=" + weight + ")");
    }
}