Modify the file ${CATALINA_HOME}/bin/catalina.bat or ${CATALINA_HOME}/bin/catalina.bat, depending on the platform. Modify the following lines:
set JPDA_TRANSPORT=dt_socket set JPDA_ADDRESS=8000
You can now start tomcat in debug mode by running catalina jpda start. From your IDE of choice you can now connect a debugging session to port 8000.