Unable to open debugger port in intellij. The port number 9009 matches the one which has been set in the configuration file for the application.
This error can happen Tomcat is already running. So make sure Tomcat isn't running in the background if you've asked Intellij to start it up ( default ).
Also, check the full output window for more errors. As a more useful error may have preceded this one ( as was the case with my configuration just now )