Are you running WebLogic from a command prompt? If so, in that same command prompt Window type CTRL-BREAK. If you are running WebLogic as a service, you will need a tool to send a SIGINT signal to the JVM. One such tool is
SendSignal But if all that you want is a heap dump, you can use the jmap utility that comes with JDK 6 to do that. (jmap also comes with JDK 5 on Linux, but not on Windows)