Preferred way of developing web applications with m2eclipse

Question

When developing Maven web applications I usually resort the the jetty-maven-plugin to quickly launch my application for local testing and debugging. Using the launch with m2eclipse has the drawback of not properly including all sources for debugging, even though they are downloaded by Maven ( see Source lookup does not seem to work ).

What is the preferred way to debug Maven web applications in Eclipse? I'd especially appreciate configurations which work with the gwt-maven-plugin.

Answer 1

Try to avoid writing code which needs a container of some kind to debug. Always write code that can run independently and wrap it in a very thin layer for deployment (thin layer -> few lines of code -> few bugs).

If you really must, try MockRunner to emulate the app server.

Other than that, you can manually add the sources in the project properties.

Answer 2

My preferred way to develop web applications with m2eclipse is to... not use it. Instead, I use the approach described in Debugging with the Maven Jetty Plugin in Eclipse that I'm quoting below:

Step 1

Go to the Run/External Tools/External Tools ..." menu item on the "Run" menu bar. Select "Program" and click the "New" button. On the "Main" tab, fill in the "Location:" as the full path to your "mvn" executable. For the "Working Directory:" select the workspace that matches your webapp. For "Arguments:" add jetty:run.

Move to the "Environment" tab and click the "New" button to add a new variable named MAVEN_OPTS with the value:

-Xdebug -Xnoagent -Djava.compiler=NONE -Xrunjdwp:transport=dt_socket,address=4000,server=y,suspend=y

If you supply suspend=n instead of suspend=y you can start immediately without running the debugger and launch the debugger at anytime you really wish to debug.

Step 2

Then, pull up the "Run/Debug/Debug ..." menu item and select "Remote Java Application" and click the "New" button. Fill in the dialog by selecting your webapp project for the "Project:" field, and ensure you are using the same port number as you specified in the address= property above.

Now all you need to do is to Run/External Tools and select the name of the maven tool setup you created in step 1 to start the plugin and then Run/Debug and select the name of the debug setup you setup in step2.

_{From instructions provided by Rolf Strijdhorst on the Maven mailing list}

Stopping Jetty

In order to stop the jetty server the "Allow termination of remote VM" should be checked in debug dialog in Step 2. When you have the jetty server running and the debugger connected you can switch to the debug perspective. In the debug view, right click on the Java HotSpot(TM) Client VM[localhost:4000] and chose terminate. This will stop the debugger and the jetty server.