Derick, This occurs because MyClass<T> is not a subclass of MyClass. Adding the <T> changes the type of the object, which means you are no longer overriding the method. Sun describes these relationships some more.
Derick, Oops! I answered the wrong question. My explanation in the above post was for why GenericReadCommandInterface<Object> and GenericReadCommandInterface<String> aren't subclasses.
Now back to your real question.
Note the difference between the two code snippets here. The second one is the one you want. This says you are implementing an interface that deals with generics. You accidently typed the first one, which would mean that you want to get rid of the type parameter. Therefore in the get method, there is no type parameter.