In Java 2(JDK 1.2), Sun starting using the Swing classes as their primary GUI source. Other than that, the real difference is the methods that are deprecated. There are a lot of methods that you can use in Java 1 that will create deprecation warnings when you run them in Java 2. For example, the Thread.stop() method is deprecated and not used anymore in Java 2. It is better to be up to date with the methods so that you avoid using these deprecated methods.