Help on java generics

I am new to Java 5 Programming and I am facing an issue with Generics
as below

In my java application , My main class is as below (I have replicated
the original scenario in the test program here )

import java.util.ArrayList;

public class TestGeneric {
    public static void main(String args[]) {

        ArrayList al = new ArrayList ();
        TestClass tc = new TestClass();
        al = tc.getList();
        System.out.println(al);

    }
}

And the TestClass is as below

import java.util.ArrayList;

public class TestClass {

    public ArrayList getList() {

        ArrayList list1 = new ArrayList();
        list1.add("Hello1");
        list1.add("Hellow1");
        ArrayList list2 = new ArrayList ();
        list2.add("Hello2");
        list2.add("Hellow2");
        ArrayList list3 = new ArrayList ();

        list3.add(list1);
        list3.add(list2);
        return list3;

    }

}

The method getList in TestClass returns as ArrayList of ArrayLists .
If I need to implement the above two class using Generics , how Can I
go about it .

Will it be ArrayList <ArrayList > al = new ArrayList <ArrayList>
(); in the main program ? or
 ArrayList <Object > al = new ArrayList <Object> ();
Please help

Thanks
Sam