I have created an applet that opens a JFileChooser to select a file on the click of a JButton. It works fine when I run it in Eclipse. When I embed
JFileChooser
JButton
Consider enabling the Java Console which will allow you to see all the exception stack traces hopefully making it easier for you to debug.
Also "appletviewer" is designed for testing applets outside a browser including allowing you to see the exceptions.