public class SecondClass extends FirstClass {
    public SecondClass() {}
    public SecondClass(int a) { super(a); }
    public SecondClass(int a,int b2) { this(a); b = b2; }
    public static void main(String[] args) {
        FirstClass fc = new SecondClass(2,4);
        System.out.println("fc: "+fc);
        SecondClass fc2 = new SecondClass(9,7);
        System.out.println("fc: "+fc+" fc2: "+fc2); } }
// Output:
// fc: FirstClass(2,4)
// fc: FirstClass(2,7) fc2: FirstClass(9,7)