The message is probably similar, but it is not the same. There are more details that tell you exactly where the "unchecked or unsafe operation" occurs. As others have pointed out, this is because you are not using generics, which are a new feature in Java 5.0. If you are interested in learning more about generics and how they are used in the Collections API, I suggest you google for more information.
subject: uncheked or unsafe operations notification