Example of using parametrised multiple bounds in Java 7.This is just showing how stuff is connected - it really does not make any sense in itself.Compiles with JDK7.

GenericsDemo.java

/*
Example of using parametrised multiple bounds in Java 7.
This is just showing how stuff is connected - it really does not make any sense in itself.
Compiles with JDK7.
 */
import java.util.ArrayList;
import java.util.List;

// parametrised interfaces
interface IF1<T>{T returnIt();}
interface IF2<T>{void doIt(T e);}

// un-parametrised multiple bounds using the above interfaces
abstract class AbstractClass1<T extends IF1 & IF2> {
    List<T> aList;
    void add(T e) {
        aList.add(e);
    }

    @SuppressWarnings("unchecked")
    void loopExecute(Object o) {
        for(T e : aList) e.doIt(o);
    }

    @SuppressWarnings("unchecked")
    Object  pop() {
        Object o = aList.remove(aList.size()-1);
        return ((T) o).returnIt();
    }
}

// parametrised multiple bounds
abstract class AbstractClass2<A,B,T extends IF1<A> & IF2<B>> {
    List<T> aList;
    void add(T e) {
        aList.add(e);
    }
    void loopExecute(B o) {
        for(T e : aList) e.doIt(o);
    }

    A  pop() {
        T o = aList.remove(aList.size()-1);
        return o.returnIt();
    }
}

// concrete implementation
// inheritence of parametrised multiple bounded class
class ConcreteClass <A,B,T extends IF1<A> & IF2<B>> extends AbstractClass2<A,B,T>{
    ConcreteClass() { aList = new ArrayList<>(); }

    void add(T e) {
        aList.add(e);
    }
    void loopExecute(B o) {
        for(T e : aList) e.doIt(o);
    }

    A  pop() {
        T o = aList.remove(aList.size()-1);
        return o.returnIt();
    }
}

public class GenericsDemo {

    public static void main(String[] arg) {

        class Dummy<T,U> implements IF1<T>,IF2<U> {
            T e;
            Dummy(T e) { this.e = e;}

            @Override
            public T returnIt() { return e; }

            @Override
            public void doIt(U param) { System.out.println(e + "DO IT ! " + param);}
        }
        class Dummy2<T,U> extends Dummy<T,U> { Dummy2(T e) { super(e); }}

        ConcreteClass<String,Integer,Dummy<String,Integer>> c = new ConcreteClass<>();

        c.add(new Dummy<String,Integer>("Jalla"));
        c.add(new Dummy2<String,Integer>("Haram!"));
        c.loopExecute(10);
    }
}