I'm working on a project with dependency X. X, in turn, depends on Y.
I used to explicitly include Y in my project's pom. However, it was not used and to make things cleaner, I instead added it to X's pom as a dependency. X is marked as a release dependency.
The problem is that after removing Y from my project's pom and adding it to X's pom, my project isn't picking it up on mvn -U clean package. I know -U update snapshots but not releases.
So, without deleting the ~/.m2/repository directory how can I force a re-download of X's pom? Also, I tried running dependency:purge-local-repository and it didn't work either.
You cannot make Maven re-download dependencies, but what you can do instead is to purge dependencies that were incorrectly downloaded using mvn dependency:purge-local-repository
See: http://maven.apache.org/plugins/maven-dependency-plugin/purge-local-repository-mojo.html
I just deleted my ~/.m2/repository and that forced a re-download ;)
I think following command may help you!
mvn -U clean install
Thanks to Ali Tokmen answer. I managed to force delete the specific local dependency with the following command:
mvn dependency:purge-local-repository -DmanualInclude=com.skyfish:utils
With this, it removes utils from my .m2/repository and it always re-download the utils JAR dependency when I run mvn clean install.
Project right click-> Maven -> Update Project and check the checkboxes as in the screen shot. It will update releases as well :)
mvn clean install -U
-U means force update of dependencies.
If you want to update a single dependency without clean or -U you could just remove it from your local repo and then build.
When you added it to X, you should have incremented X's version number i.e X-1.2
Then X-1.2 should have been installed/deployed and you should have changed your projects dependency on X to be dependent on the new version X-1.2
If you really want to force-download all dependencies, you can try to re-initialise the entire maven repository. Like in this article already described, you could use:
mvn -Dmaven.repo.local=$HOME/.my/other/repository clean install
Just delete ~/.m2/repository...../actual_path where the invalid LOC is coming as it forces to re-download the deleted jar files. Dont delete the whole repository folder instead delete the specific folder from where the error is coming.
Most answers provided above would solve the problem.
But if you use IntelliJ and want it to just fix it for you automatically, go to Maven Settings.
Build,Execution, Deployment -> Build Tools -> Maven
Disable Work Offline
Enable Always update snapshots (Switch when required)
If you know the group id of X, you can use this command to redownload all of X and it's dependencies
mvn clean dependency:purge-local-repository -DresolutionFuzziness=org.id.of.x
It does the same thing as the other answers that propose using dependency:purge-local-repository, but it only deletes and redownloads everything related to X.
Go to build path... delete existing maven library u added... click add library ... click maven managed dependencies... then click maven project settings... check resolve maven dependencies check box..it'll download all maven dependencies
来源：https://stackoverflow.com/questions/7959499/force-re-download-of-release-dependency-using-maven