Rabe3, Generics, Java, ArrayList

package generics;

import java.util.ArrayList;

public class Generics_Main {

    public static void main(String[] args) {

        // Base is abstract
        // Derivative1 extends Base
        // Derivative2 extends Base

        ArrayList<Derivative1> derivative1s = new ArrayList<>();
        ArrayList<Derivative2> derivative2s = new ArrayList<>();

        ArrayList<String> strings = new ArrayList<>();

        foo( derivative1s );
        foo( derivative2s );

        foo( strings ); // not working. if u want it to work, replace the
                        // "<K extends Base>" with "<K>"
    }

    public static <K extends Base> void foo(ArrayList<K> list) {

        // do something
        for (K k : list) {
            // do something
        }
        // do something
    }
}