If you’re a Linux user, edit the JVM options used to start the Tomcat instance, set by the tomcat/scripts/ctl.sh script.
For example, set the following:
JAVA_OPTS=%JAVA_OPTS% -server -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8082
where address is a port for your system.