How to add M2_REPO classpath variable to Eclipse IDE

Normally, when you use Maven command mvn eclipse:eclipse to convert existing Java project to support Eclipse project, Maven will create the entire dependency classpath by using the M2_REPO variable, which is not defined in Eclipse by default.

Nothing special, M2_REPO is just a normal “classpath variable” in Eclipse to find your local Maven repository.

Here, we show you two ways to add M2_REPO classpath variable into Eclipse IDE.

1. Add M2_REPO Manually

Define and add M2_REPO classpath variable manually into Eclipse IDE. Follow below steps :

1. Eclipse IDE, menu bar
2. Select Window > Preferences
3. Select Java > Build Path > Classpath Variables
4. Click on the new button > defined a new M2_REPO variable and point it to your local Maven repository
5. Done.

2. Add M2_REPO Automatically – eclipse:configure-workspace

Alternatively, you can define and add M2_REPO via Maven command “eclipse:configure-workspace“.

mvn -Declipse.workspace="your Eclipse Workspace" eclipse:configure-workspace

See an example :

C:\>mvn -Declipse.workspace="C:\Users\mkyong\workspace" eclipse:configure-workspace
[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'eclipse'.
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Default Project
[INFO]    task-segment: [eclipse:configure-workspace] (aggregator-style)
[INFO] ------------------------------------------------------------------------
[INFO] [eclipse:configure-workspace {execution: default-cli}]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1 second
[INFO] Finished at: Thu Apr 14 20:45:17 SGT 2011
[INFO] Final Memory: 9M/112M
[INFO] ------------------------------------------------------------------------

Done.

Verify M2_REPO is Added
Review classpath variable to verify that the M2_REPOis added into Eclipse IDE.

You need to add this M2_REPO classpath variable once only, and this variable is shared among all of your Eclipse’s workspace.

References

1. Add Maven repo example
2. Configure Maven workspace