Using the latest JDK1.1.6J build, debugging applets throws the following
error:

appletviewer -debug buttonactionstest.html
Initializing jdb...
[Internal debug-agent error: operation failed to complete - deadlock avoided]
sun.applet.AppletViewer not found (try the full name)

All debug flavors result in the above error:
appletviewer -debug buttonactionstest.html
appletviewer -debug file:buttonactionstest.html
appletviewer -debug http://jse.east/JDKTools/applet/buttonactionstest.html