I'm upgrading some code to Java 5 and am clearly not understanding something with Generics. I have other classes which implement Comparable once, which I've been able to implement. But now I've got a class which, due to inheritance, ends up trying to implement Comparable for 2 types. Here's my situation:
I've got the following classes/interfaces:
interface Foo extends Comparable<Foo>
interface Bar extends Comparable<Bar>
abstract class BarDescription implements Bar
class FooBar extends BarDescription implements Foo
With this, I get the error 'interface Comparable cannot be implemented more than once with different arguments...'
Why can't I have a compareTo(Foo foo) implemented in FooBar, and also a compareTo(Bar) implemented in BarDescription? Isn't this simply method overloading?
Edit: I have many classes which extend BarDescription. If I remove the type parameter for Comparable on Bar, leaving it in the raw state, then I get a bunch of compiler warnings when sorting all the classes which extend BarDescription. Would this be solved with the wildcards answer below? That answer looks quite complicated and difficult to understand for maintenance.