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.
Related
I've been asking myself this question for a couple of years but never really found the solution.
I used to work with eclipse (on maven java projects). I could import a project -let's call it 'proj-A'- and if one of proj-A's dependencies was found in the workspace with the same exact version, eclipse would use that project's source instead of the jar from the repository. This way I could edit a library and see the changes in the project that used it right away.
For example, in Eclipse, if proj-A depended on dep-B-1.2.3-SNAPSHOT, I could import proj-A and dep-B in the same workspace, and if dep-B version was 1.2.3-SNAPSHOT I could see the live changes in dep-B sources from proj-A classes.
I'm now working in scala in IntelliJ. I don't seem to be able to do that. what's the best workflow if you want to avoid publishing the library and then reloading the whole project that uses it along with all its dependencies every time?
If I import proj-A as sbt project I can find dep-B snapshot jar in the libraries (loaded from some repo, be it local or remote), and I can't see the code changes to the dep-B module imported in the same intellij project (i.e. the equivalent of eclispe workspace).
If I manually remove the dep-B jar and add the dep-B module as a dependency for proj-A I'm forced to do it everytime I reimport proj-A for some reason.
I'm not sure there's a way of doing this as straightforward as the eclipse way (automatic), but maybe you know something I don't ...
thanks
It should work out of box for dependencies, which are imported to the project as modules, no additional settings needed. At least for Java.
Just do not run a Maven goal, that would use dependencies from the repository.
I thought I understood Maven as I've worked on a few projects using it, but I seem to be having trouble creating my own project with it, so can someone correct me wherever I may be wrong?
Assuming I create a new Maven project (we'll say I did it through Eclipse or IntelliJ):
If I add a dependency to my POM file, assuming I add a public repository where that dependency can be found, shouldn't the IDE download the specified JAR and make it so that it is recognized when I use it in my code? Currently, my projects do not recognize any classes that should be found in JARs via my POM dependencies.
Assuming #1 does work, how can I determine via maven which transient dependencies I have? For example, I'm using classes from Pentaho Data Integration, and some of the plugins for it reference things like org.mozilla.javascript.*. Could maven automatically tell me that without me having to run the code, see it fail, and manually fix the dependency? There will be hundreds of those instances here, so manual fixing really isn't viable.
Here are my IntelliJ two cents:
1 - Adding a dependency in pom.xml of your project
Should indeed download the depended jar(s). You may need to approve "Import Changes" dialog if it pops in, or enable auto import.
2 - Seeing transitive dependencies
It can be achieved via Maven Dependencies Diagram - unfortunately only in IntelliJ Ultimate edition. You can use Maven Dependencies Plugin to see the dependencies tree in your favorite CLI.
Question 1: Adding a dependency
In Eclipse, depending on how you created the project, you should be able to add dependencies that are automatically recognized using the maven context menu.
Note that you should have created the project using the eclipse maven plugin so that it has maven nature.
To add dependencies/plugins from a remote repository, you can search in the resulting UI for a dependency if you know the artifactId or groupId. The plugin will pull up the deps whether the repo url is specified in the pom.xml or not.
After adding a dependency to the POM, the IDE will start downloading it and all transient dependencies as soon as you save the file.
If something goes wrong, you can try to "Update Project" from the context menu.
Question 2: Determining transitive dependencies
Transient dependencies are visible in the "Dependency Hierarchy" tab of the POM editor.
I usually default to the command line because it allows much more flexibility and functionality when tracking the dependency graph.
I am sorry but I have not worked with IntelliJ
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.
My boss asked me to convert one of our projects to use Maven to build. So I created a pom.xml file and now Maven builds the project fine and runs all the tests and everything. "Fine", my boss said, "We don't need these any more" and he deleted the /libs directory from the project, and he deleted the JRE from the classpath. That's fine, it still builds in Maven, but Eclipse shows everything that was in the jre or in /libs as unresolved in the editor. Because of all the error indications, I'm seriously considering going back to vi. How can I get it so Eclipse can do its thing?
To create the Eclipse .classpath and .project files, do the following:
mvn eclipse:eclipse
This will create references to your local Maven repository, which means that you'll have to build at least once with Maven, so that it can download the files. I believe you also have to define an Eclipse classpath variable M2_REPO (at least, I have one defined, and can't see any other reason I'd have done that).
I'll assume your boss deleted the JRE entry from the Eclipse classpath, which was dumb but not as dumb as deleting your actual JRE directory. The Maven-build classpath file should include something appropriate, or you can go into the "Build Path" dialog and add the JRE via the "Libraries" tab.
Oh never mind - I clicked the "Maven->Enable dependency management" and that fixed it. Don't know why I didn't think of it before.
Use a Maven-Eclipse plugin.
http://mevenide.codehaus.org/
http://m2eclipse.sonatype.org/
You can use plugins as Nick mentions, but you can also solve this very simply by pointing eclipse to your local maven repository.
1) create a classpath variable, M2_REPO, in your workspace. It should point to something like "c:\Document and Settings\yourname.m2repo\
2) Add the jars that you need.
These steps can also be automated with mvn eclipse:eclipse goal as well. The docs are here, I used it in the past but had some difficulties customizing it (for WTP and Spring configuration files under /.settings/ folder in the project)