I am new to Java, and I am working on a program that functions as a calculator. I have the code for the calculator written, but I need to make a GUI for it, because as of now the only way I can see output is by running it within Netbeans. I was wondering how a GUI is integrated into a program. Is it instantiated in the main class? Also, any sample programs that use a GUI, but are very simple -- such as 100 lines or less, not counting the GUI's code. That can be longer.-- would be appreciated.