While testing the Java Plug-In on Linux, the attached deadlock in the XAWT was provoked. It occurred when the Java Console was set to show, when the JRE used was an internal build, and upon loading the Clock applet from http://java.sun.com/products/plugin/1.5.0/demos/applets/Clock/example1.html .

The deadlock is intermittent and I haven't reproduced it since. However, the thread dump clearly shows the deadlock so hopefully it can be fixed via code inspection.