How to force maven update?

mvn clean install -U

-U means force update of snapshot dependencies.

Release dependencies will be updated this way if they have never been previously successfully downloaded. ref: https://stackoverflow.com/a/29020990/32453

If your local repository is somehow mucked up for release jars as opposed to snapshots (-U and --update-snapshots only update snapshots), you can purge the local repo using the following:

 mvn dependency:purge-local-repository

You probably then want to clean and install again:

 mvn dependency:purge-local-repository clean install

Lots more info available at https://maven.apache.org/plugins/maven-dependency-plugin/examples/purging-local-repository.html

-U seems to force update of all SNAPSHOT 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.

The example below if for updating slf4j-api 1.7.1-SNAPSHOT:

rm -rf ~/.m2/repository/org/slf4j/slf4j-api/1.7.1-SNAPSHOT
mvn compile

All the answers here didn't work for me. I used the hammer method:

find ~/.m2/ -name "*.lastUpdated" | xargs rm

That fixed the problem :-)

You can do effectively from Eclipse IDE. Of course if you are using it.

Project_Name->Maven->Update Project Configuration->Force Update of Snapshots/Releases

Just in case someone wants only update project's snapshot dependencies and doesn't want to install artifact:

mvn dependency:resolve -U

Don't forget to reimport dependencies in your IDE. In IDEA you need to right click on pom file and choose Maven -> Reimport

If you're unsure what is inside your local repository, I recommend to fire a build with the option:

-Dmaven.repo.local=localrepo

That way you'll ensure to build in a cleanroom environment.

In my case first I did was:

mvn clean install -U

Still it was showing same error then I closed project and again reopened it. Finally worked.

If you are using eclipse IDE then :

Select Project.

Press alt+F5, window for Update Maven Project will pop up.

Check - Force Update of Snapshots/releases and click OK.

If Using Intellij IDE

go to settings/Maven

check Always update snapshots

I used the IntelliJ IDE and I had a similar problem and to solve I clicked in "Generate Sources and Update Folders for All Projects" in Maven tab.

https://i.stack.imgur.com/stUqg.png

Previous versions of maven did not force the check for missing releases when used -U with mvn clean install, only the snapshots, though newer version supports this.

For someone still struggling with previous version, following can be helpful-

On Windows:

cd %userprofile%\.m2\repository
for /r %i in (*.lastUpdated) do del %i

On Linux:

find ~/.m2  -name "*.lastUpdated" -exec grep -q "Could not transfer" {} \; -print -exec rm {} \;

Whenever maven can't download dependencies for any reason (connectivity/not exists etc), it will add the ".error=Could not transfer artifact" in dependency-name.lastUpdate file in respective folder under $home/.m2 directory. Removing these files will force maven to try fetching the dependencies again.

I've got the error in an other context. So my solution might be useful to others who stumple upon the question:

The problem: I've copied the local repository to another computer, which has no connection to a special repository. So maven tried to check the artifacts against the invalid repository.

My solution: Remove the _maven.repositories files.

You need to check your settings.xml file under <maven_home>/conf directory.

This is one of the most annoying things about Maven. For me the following happens: If I add a dependency requesting more dependencies and more and more but have a slow connection, it seams to stop while downloading and timing out. While timing out all dependencies not yet fetched are marked with place holders in the .m2 cache and Maven will not (never) pick it up unless I remove the place holder entry from the cache (as other stated) by removing it.

So as far as I see it, Maven or more precise the Eclipse Maven plugin has a bug regarding this. Someone should report this.

It's important to add that the main difference of running mvn with -U and without -U is that -U will override your local SNAPSHOT jars with remote SNAPSHOT jars.

Local SNAPSHOT jars created from local mvn install in cases where you have other modules of your proj that generate jars.

For fixing this issue from Eclipse:

1) Add below dependency in Maven pom.xml and save the pom.xml file.

<!-- https://mvnrepository.com/artifact/com.thoughtworks.xstream/xstream -->
<dependency>
    <groupId>com.thoughtworks.xstream</groupId>
    <artifactId>xstream</artifactId>
    <version>1.3.1</version>
</dependency>

2) Go to project >> Maven >> Update Project

select the project and click OK.

3) Optional step, if it's not resolved till step 2 then do below step after doing step-1

Go to project >> Maven >> Update Project >> check in the checkbox 'Force Update of Snapshots/Releases'

select the project and click OK.

-U is used to force update maven Repo. Use

mvn -U clean install

I've got the same error with android-maps-utils dependency. Using aar type package in dependency section solve my problem. By default type is jar so It might be checked what type of dependency in repository is downloaded.

I tried all the answers here but nothing seemed to work. Restarted my computer first then ran mvn clean install -U. That solved my problem.

What maven does is, it downloads all your project's dependencies into your local repo (.m2 folder). Because of the internet causing issues with your local repo, you project is facing problems. I am not sure if this will surely help you or not but you can try deleting all the files within the repository folder inside the .m2 folder. Since there would be nothing in the local repo, maven would be forced to download the dependencies again, thus forcing an update. Generally, the .m2 folder is located at c:users:[username]:.m2

after using mvn clean install -U run as maven test also and after that update your project using maven-update project this works in my case

I had this problem for a different reason. I went to the maven repository https://mvnrepository.com looking for the latest version of spring core, which at the time was 5.0.0.M3/ The repository showed me this entry for my pom.xml:

<!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>5.0.0.M3</version>
</dependency>

Naive fool that I am, I assumed that the comment was telling me that the jar is located in the default repository.

However, after a lot of head-banging, I saw a note just below the xml saying "Note: this artifact it located at Alfresco Public repository (https://artifacts.alfresco.com/nexus/content/repositories/public/)"

So the comment in the XML is completely misleading. The jar is located in another archive, which was why Maven couldn't find it!

We can force to get latest update of release and snapshot repository with below command :

mvn --update-snapshots clean install

I had the same error and running mvn install -U and then running mvn install worked for me.

mvn clean install -U doesn't work. However mvn -U clean followed by mvn clean install does.

I ran into this recently and running the following fixed all the problems

mvn -fae install