I'm using m2eclipse as my maven 2 plugin for eclipse. I'm brand new to maven, so my mistake might be simple, although searching has not yielded any solutions for me. I can run maven from the command line and it build successfully. However if I import as an existing maven project, or use mvn eclipse:eclipse and then import I get the artifacts not found in my POM file resulting in no maven dependencies being loaded at all.
What's odd is that I have 2 projects, both children to a parent pom packaged project. One child loads all my maven dependencies while the other cannot find any and says my pom file is missing artifacts. Again, I can install and package them all just fine from the command line.
I even tried loading my projects into netbeans which worked flawlessly, however I am required to use eclipse.
Any ideas on how to fix this?
Update
Directory structure, pom files layout:
--main
--pom.xml (is a pom package that is the parent to two other projects)
--ProjectA
--pom.xml
--ProjectB
--pom.xml
Main is the parent project of both ProjectA and ProjectB. ProjectB has ProjectA as a dependency. Apprently m2eclipse is not happy about that depedency. As soon as I remove the dependency of ProjectA from ProjectB's pom file all the maven dependencies are found by eclipse.
- com.company.myproj:app:6.6.0:jar Missing: ---------- 1) com.company.myproj:main:pom:${myproj.version} ---------- 1 required artifact is missing. for artifact: com.company.myproj:main:pom:$
{myproj.version} from the specified remote repositories: apache-incubating (http://people.apache.org/repo/m2-incubating-repository/, releases=true, snapshots=true), central (http://
repo1.maven.org/maven2, releases=true, snapshots=false)
However, I still need ProjectB to have that dependency for ProjectA. The error message seems to be m2eclipse looking for ProjectA in a remote repo. Project A should only be in .m2 directory, but I'm not sure how to tell m2eclipse to look there.
I think this may be just a m2eclipse specific issue because using mvn from the command line works fine and like I said previously, netbeans loads the projects and dependencies just fine.
I had this issue for dependencies that were created in other projects. Downloaded thirdparty dependencies showed up fine in the build path, but not a library that I had created.
SOLUTION: In the project that is not building correctly, right-click on the project and choose Properties, and then Maven. Uncheck the box labeled "Resolve dependencies from Workspace projects", hit Apply, and then OK. Right-click again on your project and do a Maven->Update Snapshots (or Update Dependencies) and your errors should go away when your project rebuilds (automatically if you have auto-build enabled).
It sounds like your m2eclipse install is using the embedded Maven, which has its own repository (located under user home) and settings.
If you open up the Maven preferences (Window->Preferences->Maven->Installations, you can add your Maven installation by selecting Add... then browsing to the M2_HOME directory.
(source: sonatype.com)
For more details see the m2eclipse book
For me maven was downloading the dependency but was unable to add it to the classpath. I saw my .classpath of the project,it didnt have any maven-related entry. When I added
<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER"/>
the issue got resolved for me.
One of the reason I found was why it doesn't find a jar from repository might be because the .pom file for that particular jar might be missing or corrupt. Just correct it and try to load from local repository.
Okay I fixed this thing. Had to first convert the projects to Maven Projects, then remove them from the Eclipse workspace, and then re-import them.
I had problems with using m2eclipse (i.e. it did not appear to be installed at all) but I develop a project using IAM - maven plugin for eclipse supported by Eclipse Foundation (or hosted or something like that).
I had sometimes problems as sometimes some strange error appeared for project (it couldn't move something) but simple command (run from eclipse as task or from console) + refresh (F5) solved all problems:
mvn clean
However please note that I created project in eclipse. However I modified pom.xml by hand.
This could be a problem if you are using a custom 'Settings.xml', with a different <localRepository> configured in it.
Eclipse will be using the default installation of MAVEN, and will be using the default location for the User to look for the local Maven repository, which on Linux systems would be '/home/${USER}/.m2/'
Eclipse can be easily configured to use the customized 'Settings.xml', by doing the following:
Goto -> Window -> Preferences -> Select 'Maven' -> Select 'User Settings'
Under 'User Settings', select the custom 'Settings.xml' file, for 'User Settings' by clicking 'Browse' and selecting the customized 'Settings.xml'.
Click on 'Update Settings', if the 'Local Repository' Textbox does not show the custom location from the file above, just key in the location and click 'Reindex'.
Click 'OK'
After this, you could proceed to select your project from the 'Project Explorer', right click, Select 'Maven' > 'Update Project'. Make sure that your project is selected (ticked) in the Window, and click 'OK'.
This should help to resolve the issue, if using custom 'Settings.xml' for Maven.
Hope it helps.
Related
I’m using Eclipse Mars with Maven (v 3.3). When I update a dependency in my pom (change the version), my Eclipse-Maven project doesn’t pick it up, even when I right click my project, and select “Maven” -> “Update Project.” I know this because I do not see compilation errors in the Eclipse Java editor that I see when I build the project on the command line using
mvn clean install
When I remove the project from the workspace and re-import it, then things get back to normal. However this is a cumbersome process. How do I get my Maven-Eclipse project to automatically detect changes in my pom and update the project libraries appropriately?
And yes, in the “Project” menu, “Build Automatically” is checked.
When you import the project into Eclipse, use Eclipse's own built-in Maven support (aka, m2e). I recommend against using mvn eclipse:eclipse as it doesn't give the best results (as you're seeing). Maven is a build and dependency management tool, not an IDE; expecting it to manage IDE-specific stuff is silly, in my opinion (I realize the Maven team thinks differently, that Maven should be responsible for managing your IDE, but that's nonsense).
So if you have the project available on your system, delete any Eclipse-specific files (typically just .classpath, .project, and folder .settings), they were generated by mvn eclipse:eclipse and you don't want them interfering with the "proper" import process described here. Then inside Eclipse, use File > Import > Maven > Existing Maven Projects to import the project. That should result in better integration between Eclipse and maven, including automatically updating the Eclipse build path when the pom is changed.
As a quick check, after doing the import that way, you should see a group called Maven Dependencies in the Libraries tab of the project's Build Path (in Properties dialog). Like this:
If you want the Eclipse project configuration to be automatically updated every time the pom is changed, there's a (experimental) setting for that under Preferences > Maven. Be aware that doing so might not be desirable, though - as mentioned in this feature request, it's a somewhat lengthy process that touches a bunch of stuff in the Eclipse Project; doing that automatically on every pom.xml change could end up being more trouble than it's worth.
Three Mandatory checks you should do for automatic update in your classpath
Your Repository is not in-sync with your Eclipse IDE, Please check the below settings in your IDE.
Right Click your any POM.xml from your IDE and check for the Maven profile which should be auto-activated. Also offline and Force update check box shouldn't be enabled. Please refer the below image.
Always check for your user settings which should reflect your local maven settings.xml, as shown in the below figure.
After performing all these checks, refresh your Eclipse Work-space to get these changes reflected.
Eclipse should be updating your classpath. If it's not, that implies something is going wrong.
It's hard to say what the problem could be exactly without knowing more about your project's pom.xml. More information might be necessary to solve the issue, but I'll just make a stab in the dark:
Open the .project file in your project's root folder and check the ordering of builders and natures there. It might be possible that some other nature on the project is also causing maven2Nature to fail. Move maven nature up and see if that helps any.
Alternatively you might be thinking that Eclipse does not update your dependencies because it does not add some some error indicators in the project that should be there with new dependencies. If that's the case try cleaning the current project (project>clean...). Maven in Eclipse does not necessarily trigger a full rebuild when dependencies are updated.
If none of this works, closing/opening the project might solve the issue quicker than re-importing.
What you wrote, should work. Did you check this:
does "pure" mvn install from terminal see your changes in POM?
maybe some Maybe plugin is buggy, cached some dependencies in target, and mvn clean install is needed
you can run Eclipse in a new workspace, and import your project there, sometimes it helps in case of such strange problems
instead of importing Maven project to Eclipse via m2eclipse, you can try to create Eclipse files via the old mvn eclipse:eclipse and see what happens then
does it work well when you try to import your Maven project to other IDE, the free IntelliJ Community Edition for example?
As a last resort, you can delete your current Eclipse installation and install a new version. When you add several plugins, they might interfere with one another and create weird behavior. After you do that, do not import your Maven project into your workspace, but rather create a new one and copy and paste the files that you had.
I have a maven project that depends on a jar (say A). When running the project, it uses the jar under Maven dependencies.
I have the source of A with me and its opened as a project in Eclipse. When I run the project I need to use the source and not the jar. How do I tell Eclipse to use the source and not the jar?
m2eclipse does this by default, if that is a full Maven project. See the context menu in the screen shot of http://www.sonatype.com/books/m2eclipse-book/reference/eclipse.html#eclipse-sect-resolving-dependencies, where it says "Disable workspace resolution".
If you don't find that context menu entry for your project, then you probably have a Java project with a POM file, which is not marked as Maven project type in Eclipse. Use the context menu Configure->Convert to Maven project in that case.
I had problems with the workspace resolution of m2eclipse as well. It would recognize the dependency (A) and show a different icon in the dependency view (which indicates that the dependency is resolved from the workspace) but the classes were not found.
Only when I ran a mvn install on project A all artifacts were generated and the resolution started to work. Maybe that helps.
Also I found a couple of hints (related to not working workspace resulotion) that suggested to (re-)import the project again using "Existing Maven Projects" wizard.
I have multiple related projects open in a workspace in eclipse. One of the projects has a maven dependency on the output jar from another project. In this project, any references to the classes in the dependency always show up as red (unidentified) and I get no code completion or javadoc showing up for them. If I manually add the jar to the classpath, then I no longer have this problem. The thing is, I don't want to have to manually add the jar every time our revision changes, that's what Maven is for. Any ideas on how I can resolve this? it seems like a bug to me, but I'm not sure...
The correct way to do this is the following:
Make sure that m2e or m2eclipse (depending on your version of Eclipse) is installed: http://www.eclipse.org/m2e/
Use the dependencies section in the POM file exclusively, don't fiddle with the Eclipse project references. Right-click the project, then select Maven > Update Project Configuration to reset the project to the Maven default settings. This way, m2e has ownership of the dependencies.
If you don't have that option, you might need to enable the project for Maven usage. Right-click the project, then Maven > Enable Workspace Resolution or Maven > Enable Dependency Management.
Make sure all referenced projects are open in Eclipse and have the Maven nature enabled.
Check the Maven settings for each project, make sure that groupId, artifactId and version match with the projects you have open in Eclipse. So if the project you depend on has version 1.0.0-SNAPSHOT in Eclipse, make sure that the depending project's POM file references version 1.0.0-SNAPSHOT in the dependencies section.
Enable Workspace Resolution for each of the projects. Right-click the project, then Maven > Enable Workspace Resolution.
Finally, if the projects are still not resolved, right-click the project again, then Maven > Update Dependencies
This should solve your problem.
I had the same issue and resolved the problem by right-clicking on the project and selecting Maven -> Disable Workspace Resolution from the context menu. I had already tried updating the project from the POM file as described above.
In order to fix this typically you can copy the Eclipse .classpath file from a working project since there isn’t anything project specific here assuming you’re structured as a standard Maven project. This will tell Eclipse to allow Maven to manage the dependencies and build. There seems to be no easy way to do this from the Eclipse UI.
he fellas, i need your help again.
Im trying to develop a new part for an existing software. The parts are all done using Maven. I have to work in several projects at once, which are all continously opened in Eclipse. In Eclipse i use M2E, but i tend to edit the poms directly in xml.
So, now I can build (clean install) the projects individually, works ok. But Eclipse now has problems with the online help: It shows me errors. Eclipse cant seem to see classes which are placed in the same project, but different packages. Note that it works fine when i compile it!
Also after I run the pom the dependencies dont show up as "Maven Dependencies" but as "Referenced Libraries".
This persists after I run mvn eclipse:eclipse from outside and refresh.
Thanks so much for your help!
"Do not ever do mvn eclipse:eclipse", only do mvn eclipse:clean from command line first and then import "as maven projects" using your eclipse M2E plugin.
M2E Plugin knows how to handle Maven Dependencies, whereas mvn eclipse:eclipse knows how to handle Referenced Libraries, and they are NOT compatible with each other. You can always do mvn update project in Eclipse after mvn eclipse:clean.
I had to delete the maven-project, too, after using eclipse:eclipse. It added the references as "Referenced Libraries".
Manually deleting the .project and .settings files in the project folder and importing the project again helped. I used the M2E import. Afterwards it displayed the libraries within the "Maven Dependencies". Subsequently I was able to run it on my local webserver.
I do not really know the reason for the behavior, but deleting the project and reimporting it solved it.
I agree with kisna. As an alternative to fix the project if already contains both "Referenced Libraries" and "Maven Dependencies", you can do the following:
https://docs.oracle.com/cd/E14545_01/help/oracle.eclipse.tools.weblogic.doc/html/j2eelib/operations/opRemoveLibRefFromClasspath.html
Right-click on the project and select Properties -> Java Build Path -> Libraries tab -> Find the entry in the list of libraries called Shared Library [] or/and all libraries that starts with 'M2_REPO/', and then select it/them and remove.
I'm having maven project on Eclipse with m2eclipse plugin. This project has some dependencies. Some of them are libraries as slf4j, apache-commons etc. But there are also mine libraries, that I'm developing simultaneously in eclipse. Unfortunately m2eclipse creates build path in such a way that my libraries are added to the classpath not as a JAR archives from M2 repository but as class files from /target/classes directory. For that reason I can not use maven-shade-plugin beacuse I'm gettin a message:
" Error creating shaded jar: error in opening zip file /home/user/workspace/my-project/project-a/target/classes".
When I'm building project-a from command line using mvn clean install everything works well - shaded JAR is generated. How to fix it?
After few hours of searching I've already found solution. This can be made by configurinng Maven Build Configuration
1. Select arrow on Run as.. button
2. Select Run configurations...
3. Select yours project Maven Builder
4. On the right tab (Main tab) deselect: Resolve Workspace artifacts.
Click Apply and build your project - all will work as you wish :).