Ofer, Look at the articles in the link already given - http://wiki.apache.org/tomcat/HowTo#How_do_I_obtain_a_thread_dump_of_my_running_webapp_.3F- find the bit about sendsignal. Download this program, and run it. This provides the windows equivalent of sending -3 to a *nix java process, e.g. encourages it to provide a thread dump. I have used in the past on windows with great success. Requires no changes to get it to run, e.g. you do not have to restart a process or configure it
HTH Chris