new maven POM file in eclipse java project - eclipse

Have upgraded to eclipse.indigo using a new installation. Added m2e. Maven shows up under Windows>Preferences. File>New>Other>Maven gets the following options: Checkout ..., Maven Module, Maven Project. The Maven POM file option is missing. I'm trying to add Maven support to an existing Java project. Have read the manuals, searches, helps, etc. No explanation as to why the Add POM option is missing. Any idea how to get this option to appear?

In order to create a POM on your project, and also change the project structure to Maven default, right-click on your project > Configure > Convert to Maven Project.
Don't forget to choose the correct Packaging type (in your case I guess it will be POM).

I don't have this option either, seems to have disappeared with the latest version. This bug report seems to point in this direction as well:
https://issues.sonatype.org/browse/MNGECLIPSE-2709
The standard way should be to create a new Maven project through the wizard, which will then also contain a POM file. You could use that to create a dummy project and then copy over the POM file.
In most cases, I also just copy an existing POM file to the project and start with that.

Quick workaround: Adding a POM by hand. (Also I'm not sure that I've ever seen an "Add POM" option.)
Simply add a file to your project (New > General > File), and name it pom.xml. On double-click on this file, the POM Editor will open.

Related

Tell eclipse to use Source and not Jar

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.

Maven dependency issue in eclipse

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.

Eclipse doesn't compile classes in source/main/resources directory in maven project

I have created a maven project in eclipse using the maven2eclipse plugin.
I then convert the project to a web module project by going to project facets in the project properties.
The problem is that when I attempt to create a class under the directory src/main/resources, none of my classes compile. I can put any sort of junk in the classes and the compiler doesn't give me any warnings. Also, the package I create doesn't create a "brown package" but a folder instead.
Does anyone know what I have configured wrong?
src/main/resources is intended to hold... resources: properties files, images, etc. that are copied to the classes directory. Java source files must be put in src/main/java.
You can try this : right click on your project > maven > update project configuration. It will configure you .classpath and .settings against your pom.xml configuration.
The problem was that when you switch to this web module in project facets, the "exclude *.java" files is entered under java build path > source by default. This must be removed.

How to have Netbeans projects export their dependencies like Eclipse does?

In Eclipse, if a project uses a particular JAR file, I can mark it to provide/export it.
So if another project has a reference to the former, then the particular JAR will be available too.
How can I do that in Netbeans?
In Netbeans you always have to add JAR in the project properties, unless you use some deployment tools.
Right click in your project
Project Properties -> Libraries
Add JAR

m2eclipse not finding maven dependencies, artifacts not found

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.