Import Maven Project into Eclipse w/ Style (Maven + Eclipse pt. 3)

The problem:

You have a Maven 2 project, and would like to work on it in Eclipse. Oh, and you want the Maven plug in for Eclipse configured on this project too!

The solution:

The first thing I do when I check out a Maven project is generate the Eclipse project files. Start by going to the project's root folder and typing:

mvn eclipse:eclipse

This will create the files Eclipse uses to understand the project, .project and .classpath. There are links to the jars configured via the pom in the .classpath file. You will want to get rid of these, because the Maven plug in will handle dependency configuration. Go into the .classpath file and delete all "classpathentry" nodes that have "M2_REPO" in the path attribute value. Now save this file.

At this point your project should have errors. Eclipse cannot find the jars needed to build properly. Worry not. Now we will enable the Maven plug in. Right click on the project root node in the package explorer to bring up the menu. Select "Maven" and then "enable". After a bit of processing your project should rebuild. Now you have the benefits of the Maven plug in!

Eclipse Plugin for Maven 2 Development (Maven + Eclipse pt. 2)

The problem:

You use the Maven 2 system for your projects. You use Eclipse to write your Java code, and things like running and debugging applications.

The solution:

Get the Maven 2 plug in for Eclipse! This is a very nice plugin. This plug in will handle configuring your projects class path. It will add the dependencies defined in your pom to the class path. It will also add and remove dependencies from the class path as you add or remove them in the pom file. It comes with a nice little wizard allowing searching of dependencies, with the ability to add them into your pom with a simple click. This wizard can also be configured to search on the dependencies installed in your local repository.

You can find the plugin here. If you like using the Eclipse plugin manager use this url: http://m2eclipse.codehaus.org/update/

Once you have installed the plug in you can create "Maven 2" projects that are configured in the Maven standard format (you know "src/main/java", "src/test/java" folders etc.). You can also right click a project select the "Maven2" option and select "enable". This will configure your project's class path using the project's pom. Note that this means your project must have a pom! Now Eclipse will have access to all classes contained within the jars managed by Maven.

This is great, but wait there is more. You of course will want to run Maven commands from within Eclipse, because having to go back and forth between the IDE and command line is just too much work. Worry not, just go to the "Run" menu, select "External Tools" and select the "External Tools..." menu item. This will bring up a menu where you should see a category called "m2 build". By clicking on this category you can create new launchers for doing Maven commands. One word of caution I've found some, more complex, Maven commands did not work great this way. The one in particular was the "jetty:run" command.

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Maven Plugin for Generating Eclipse projects (Maven + Eclipse Pt. 1)

The problem:

You want to use the ubiquitous IDE, Eclipse, with your Maven project.

The solution:

Just because you use Maven doesn't mean that you are going to jump through hoops to make it work with Eclipse; all you need to do is type "mvn eclipse:eclipse". This command will generate the .classpath and .project files that Eclipse needs so that it can understand your project.

Once you run this command in your project boot up Eclipse and click File -> import -> General -> Existing projects into workspace -> next, now use the enabled browse button to find the project's root directory. Once you do this click OK. You should see your project in the projects window. Make sure it is selected and press the "Finish" button.

Right now you probably see all sorts of errors. LOL. One last thing. You must create an Eclipse classpath variable that points to your local Maven repository. Click the following: "Window -> Preferences... -> Java -> Build Path -> Classpath Variables". You now shall click "new" button and create a variable with name "M2_REPO" and value being where your local Maven repo is found. Usually this is ${HOME_DIR}/.m2/repository. On my OS X machine this is "/Users/ottaway/.m2/repository". On my Windows machine it is "C:\Documents and Settings\rob\.m2\repository". Once you set this press the "OK" button.

Your projects dependencies should now be loaded. Note that if you add new dependencies to your project you will need to run the "mvn eclipse:eclipse" command again. This will regenerate the .classpath file that contains the dependencies.