Debugging Maven Tests by Connecting an IDE to the Maven JVM

In some instances you cannot reproduce a failure or condition running a test in an IDE that manifests itself when you run it on your build server or via maven on the command line.

In that case, it is very helpful to be able to remotely attach your IDE to the running maven process and then step through the code.

To do so you will need to:

Execute maven on  the command line as follows (adding any additional -D args as required by your project):

mvn -Dmaven.surefire.debug test -pl module-in-question

This will run the maven automatically pausing the JVM awaiting for a remote debugger to connect to port 5005.  If you want to have it listen on a different port you can pass it in as follows:

mvn -Dmaven.surefire.debug="-Xdebug  -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8081 -Xnoagent -Djava.compiler=NONE" test -pl module-in-question

Create a debugging run profile in either Eclipse or IntelliJ or your favorite IDE configured to connect to a JVM listening on the specified port.

Then once you have run maven on the command line, simply execute the run configuration in your IDE and debug your application as usual.

If need be, you can run the maven JVM on the cli such that maven does not fork the tests as follows:

mvnDebug -DforkCount=0 test