You need to know what's in the Java libraries if you want to write to the Java libraries. If your code is all self contained, then you don't. So - open a Swin

You need to know what's in the Java libraries if you want to write to the Java libraries. If your code is all self contained, then you don't. So - open a Swing JFrame and you need to know where that is in the API and how to call it.