Is any way to view the actual code behind the default classes in Java (java.awt.*;, javax.swing.*;, etc) to see exactly what it is that is
I also find http://www.codeatlas.com to be a great place to look for JVM based source code in general. For example, if you are ever looking for how java.awt.ActionEvent is implemented you can find it here:
http://www.codatlas.com/project/L_fXVCOhW4_lzXEd3R5DNQ__/master/src/share/classes/java/awt/event/ActionEvent.java?keyword=ActionEvent&line=59
What's nice about it is that it gives an IDE like browsing experience by adding cross-reference and syntax highlighting.