Press a button and check it out !!
This app begins to use the GUI tools included in the JAVA
AWT (Abstract Windows Toolkit). Stuff like buttons, checkboxes,
Radio buttons, you know,... Widgets! Anyway this is the first app
making use of a GUI component and showing how to detect an event
from it and handle it (Callbacks). It only has buttons and
a TextArea field, but it give you a feel for things to come.