A subclass can add its own type parameters, if needed. : Generic Class Hierarchies « Generics « Java Tutorial

1. Java Tutorial
2. Generics
3. Generic Class Hierarchies

class Gen<T> {
  T ob; 

  Gen(T o) {
    ob = o;
  }

  T getob() {
    return ob;
  }
}


class Gen2<T, V> extends Gen<T> {
  V ob2;

  Gen2(T o, V o2) {
    super(o);
    ob2 = o2;
  }

  V getob2() {
    return ob2;
  }
}

public class MainClass {
  public static void main(String args[]) {
    Gen2<String, Integer> x = new Gen2<String, Integer>("Value is: ", 99);
    System.out.print(x.getob());
    System.out.println(x.getob2());
  }
}

Value is: 99