Java: Same name but different generic type

Question

I wanna use an ArrayList for my Code but it should contain different types of Objects. So it should be sth like this:

 switch (foo) {
        case "foo1":
            list=new ArrayList<foo1>();
            break;
        case "foo2":
            list = new ArrayList<foo2>();
            break;

I know the posted Code does not work but is it possible to make sth similar.

And before you ask there should be multiple actions performed on this List but i dont wont to write everything again just with a different name for the List.

public class foo1 {}

public class foo2 {}

    import java.util.ArrayList;
public class work{
    public static void main(String[] args){
    ArrayList<?> list;
     switch (args[0]) {
            case "foo1":
                list=new ArrayList<foo1>();
                break;
            case "foo2":
                 list= new ArrayList<foo2>();
                break;
            default:
                System.out.println("Some Error Text");
                return;

        }
     list.add(new foo1());
    }
}

Answer 1

What you're asking for is entirely pointless because of type erasure. Type parameters cease to exist at run time, so the thing you get from new ArrayList<Foo1> is exactly the same as the thing you get from new ArrayList<Foo2> .

In other words, type parameters are information for the compiler only. And with the code that you're working with, the compiler really only cares about the declared type of list , not the type that you supply when you instantiate it.

Of course, your code will compile if you've declared

ArrayList<?> list;

or

List<?> list;

or you can narrow it down if Foo1 and Foo2 have a common supertype (other than Object ) - say they are both subtypes of Foo , you can write

List<? extends Foo> list;

but why would you bother?