How can I reference another workspace project using Eclipse m2e?
Do I have to add a project dependency in the project setting? But in that case the dependency is not shown in the pom.
If I set them in the pom, it will not reference the project in workspace but reference the jar in the local repository. Quite annoying, anyone can help?
The correct way to do this is the following:
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.
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 Project
This should solve your problem. If after this, your dependencies are still referenced from the file system, check the groupId, artifactId and especially version of each dependency again.
Also check if you don't have any errors in your project - try to run Maven install.
I'd go even further than this.
If you've ever run mvn eclipse:eclipse on your project then you're probably in trouble. I had a situation where I had both a "Referenced Libraries" section and a "Maven Dependencies" section in my eclipse project, with conflicting library versions, causing eclipse and myself inevitable confusion.
The safest thing I found was to run mvn eclipse:clean from the command line then go back in to eclipse, refresh the project, "OK" the resulting problem dialog, and then go Maven > Update Project. This sorted it all out for me.
When eclipse is messed up with importing and deleting several projects, you may need to rebuild index of maven repositories. Here is a way that I have done.
Check if an referenced project is recognized as a maven project by eclipse properly.
In menu bar, click Window -> Show View -> Other...
When 'Show View' window pops up, select Maven -> Maven Repositories
In Maven Repositories window, You should see your project as jar file in Local Repositories -> Workspace Projects
If you can not find your project in Workspace Projects, right click on Workspace Projects and select Rebuild Index.
Update maven of an referencing project
Right click on the referencing project, Maven -> Update Project... -> OK
You also need to make sure that you are running the correct goals.
If you don't run the install goal then it won't be copied to your repository and won't compile.
To learn more about goals have a look at https://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html
With kudos to #nwinkler's response, the main problem is matching the version number.
A common scenario is that if you are developing a set of projects that are version lock-steped with each other - for example, a project and a set of library projects that are not very loosely coupled, such that a library API might change in a version to be consumed by the relevant app project version, but may change in a way that is incompatible with a past or future version of the app project.
The correct way to set Maven dependencies in such a configuration (and it is also the recommended practice) is to have the app consume specific versions of the libraries - so, for example, if you rebuild an old version of the app, it will use the library version that it previously compiled with.
With the app project's POM library dependency set to a release version (lets say 1.0.0), and while working on the next release with both the app and library projects set to a SNAPSHOT release (lets say 2.0.0-SNAPSHOT), the m2e will not resolve the library version correctly, and will likely download an old version, so that trying to use Eclipse features like "Open Decleration" will target the download jar (sometimes without even a source attachment) which can be pretty annoying.
One way to work around that is to set the app POM dependency version to a range, so instead of depending on 1.0.0, you'd depend on [1.0.0-). With an open range like that, m2e will happily find your workspace library project. But you'd want to set it back to the "correct" version before committing, building and publishing - and this can be very error prone.
My solution is to use build profiles and set a custom profile for m2e, like this:
Set your dependency version with a property, to the version you want to publish against:
...
<properties>
<my.library.version>1.0.0</my.library.version>
</properties>
<dependencies>
<dependency>
<groupId>my.group</groupId>
<artifactId>my.library</artifactId>
<version>${my.library.version}</version>
</dependency>
</dependencies>
...
Then add a profile section with an active by default profile that does nothing, and an Eclipse-specific profile that overrides the library version property with a range:
...
<profiles>
<profile>
<id>default</id>
<activation><activeByDefault></activeByDefault></activation>
</profile>
<profile>
<id>eclipse</id>
<properties>
<my.library.version>[1,)</my.library.version>
</properties>
</profile>
</profiles>
...
Finally go to your project properties, and under "Maven" type "eclipse" into "Active Maven Profiles":
Then "Apply and close".
Eclipse m2e will then always see the version range and will resolve dependencies from the eclipse project (even if you have the library installed in the local Maven repo, as the Eclipse project will have a higher version number), but other builders will see the original, strict, version number.
Related
I am using Maven to use Postrgres SQL driver. Besides I am using InteliJ IDEA Ultimatre Edition, and, as I understood, Maven is included in Ultimate version initially. Correct me - all I need, is to set dependencies, and connect PostrgeSQL to Java. I am not oblige to Download Maven (except required Dependecie of course, I mean Maven as framework)? Thanks a lot!
When you are creating a new project, choose Maven. After the project is created, you will receive an empty Maven project structure with the pom.xml and a script mvnw of Maven Wrapper, which you can use (instead of mvn) to build your app.
Just add dependencies to the pom.xml and build.
The Maven Wrapper will do the work for you - download Maven into the project subdirectory and use it.
I have cloned the git repository from https://github.com/viatra/org.eclipse.viatra.examples
and imported the project incquery-demo-generic (located in /query/headless-maven) as a Maven Project in Eclipse. Unfortunately I get the following error when I open the project's pom.xml:
Furthermore everytime when I click on "Run As" -> "Maven install" or "Maven build..." I get the following error message in the console:
Failed to execute goal on project incquery-demo-generic: Could not resolve dependencies for project hu.bme.mit.incquery:incquery-demo-generic:jar:0.0.1-SNAPSHOT: Failed to collect dependencies at org.eclipse.incquery:runtime:jar:0.8.0-SNAPSHOT: Failed to read artifact descriptor for org.eclipse.incquery:runtime:jar:0.8.0-SNAPSHOT: Failure to find org.eclipse.incquery:org.eclipse.incquery.parent:pom:0.8.0-SNAPSHOT in https://repo.eclipse.org/content/repositories/emf-incquery-snapshots/ was cached in the local repository, resolution will not be reattempted until the update interval of incquery-snapshot has elapsed or updates are forced -> [Help 1]
Blockquote
In the Maven Dependencies Folder I can find some, but not all necessary jar files.
I have tried "Project clean", "Maven update", "Maven build... (Goal: clean package)" and to delete the .m2 repository and to re-build the maven project, but nothing helps.
I also tried to download some dependencies as .jar files and add them to the build-path, but they contain nothing but pom.xml and properties-files themself, thus I keep getting "cannot be resolved to a type" errors in relevant parts of the Java src-code.
Can somebody successfully run this project in her/his eclipse?
I am not an expert on Maven Projects so please tell me what to do in "layman words".
Thanks & kind regards,
MCRaven
The projects in the VIATRA examples repository (I notice it as one of the committers of the VIATRA project) are somewhat unusual: they are Eclipse plug-in projects that have Maven build informations added via Maven Tycho.
One more thing here: the 0.8.0 version of EMF-IncQuery bundles was released in 2014, thus it makes sense that the corresponding snapshot versions are removed. This means to me that this example was not updated for a long time. This is somewhat by design - some examples are not updated for each released version, but they are not are still available for references. If you are explicitly interested in this example, please contact us on VIATRA project forums or Bugzilla and we will provide example-specific support there.
Inside Eclipse we usually not rely on Maven (and our experience is that Tycho-based projects often does not work with M2E correctly). You could try to update Maven dependencies for the org.eclipse.incquery projects to 0.8.0, but I am still unsure whether it will work or not.
On the other hand, I'd rather suggest to install the old EMF-IncQuery version into your Eclipse instance and then simply rely on the Java Development Tools and the Plugin Development Environment to compile the project, and simply ignore any errors in the Maven descriptors for now.
I'm having something quite peculiar here, my build is successful in maven when I type "mvn clean install" however once imported into Eclipse it's showing errors.
See for yourself:
I guess exluding quartz from the `pom.xml solved the problem but I'd like to know why.
PS: Here is the pom.xml in case you want to see it:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.nantes.mpclient</groupId>
<artifactId>MyClient</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>MyClient</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.nantes.mp</groupId>
<artifactId>MyEjb</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.jboss.jbossas</groupId>
<artifactId>jboss-as-client</artifactId>
<version>5.1.0.GA</version>
<type>pom</type>
</dependency>
</dependencies>
</project>
###EDIT
As you can see quartz is here:
Updating maven project after importing it has fixed this issue for me:
Right click on the project --> Maven --> Update project.
Sometimes I get these types of issues as well.
Generally, what worked best for me with Eclipse & Maven:
Use the latest m2e Eclipse plugin
Use Maven 3
Make sure m2e uses the same Maven version as the one you're using on the command line (not the internal one)
Import projects as Maven projects to generate the Eclipse project files
The other upvoted answers did not work for me using these versions:
Eclipse Neon
Maven 3
m2e 1.7
This is what I had to do:
Delete the Eclipse project from Eclipse interface (do not delete project contents on disk)
Go to the project's root directory in a file explorer or terminal
Delete these files: .classpath, .project, and .settings directory
Back to Eclipse, File -> Import... -> Maven -> Existing Maven projects
If you don't see any error in Eclipse project but it keeps showing the red icon on your project name. Try mvn eclipse:eclipse.
Then select all projects in Eclipse, Right click > Maven > Update projects
Hope it helps.
You should try mvn eclipse:eclipse
And then make sure the M2_REPO variable is point to your local repository.
sometimes maven update nor all above works.
so check which import statement gives you error, then go particular lib file which is usually in c:user/ur-PC-NAME/.m2 get into package delete that .jar file.
then in eclipse, right click on project > maven > update maven.
Sometimes the m2e "maintained" eclipse project is out-of-sync with the actual project in POM (There are lots of reason for that). Assume you have using m2e 0.8 or later, right click on the project, under Maven, there are two entries that are usually useful. They are Update Dependencies and Update Project Configuration
Have a try on them, wait a while after u clicked that for eclipse to update the project and build. Normally it solves similar problems.
That often happens when the m2eclipse hasn't updated the build path to correspond to what a modified POM file says. There's an entry in the Maven context menu to update the Configuration.
In my case,
I just deleted project from Eclipse (not ticked checkbox to delete
from project location).
Opened project as "Existing Maven Project" again.
and it solved my issue.
I found that my project was using a project specific Java Compiler setting set to Java 1.5. Furthermore, the project facets were still referencing Java 1.5 when Maven, m2e, Eclipse general Java Compiler settings were all set to Java 1.8.
In my case there were also problems with Java build path like the following:
"Build path specifies execution environment J2SE-1.5. There are no JREs installed in the workspace that are strictly compatible with this environment." Fixing this resolved compilation errors.
You've a library (quartz-1.5.2.jar) that's reference to your m2 local repository which doesn't exist if you just remove the quartz from your build path and update your dependencies internally(in eclipse) that would solve the problem
Try to use different/older version of JRE. In my case switching back to JRE7 from JRE8 eliminated the problem.
Delete and Re-Import the project in eclipse (without deleting files of course). Unlike other answers I have not looked into why this happens but it works. poof - compilations errors be-gone
It may help: After upgrading eclipse or changing it or something like, old eclipse specific files (.classpath, .project, and .settings) may not be compatible to the new version of eclipse. So you may have to re generate this eclipse specific files using Maven. So try this in your eclipse project root
mvn eclipse:eclipse
In my case, eclipse starts to show all errors after I changed some versions of dependencies in pom.xml, however the command line mvn clean install build successfully
I deleted folders of the dependencies I changed manually from the .m2 repositories (in my case everything under org.apache.beam), because I also has corrupted dependency issues.
mvn clean build the project, this downloaded the dependencies again
right click project: maven -> update project
delete the project from eclipse (but not from disk) and reimport (this actually left me with 1 error still, then i delete and reimported again)
Go to Eclipse> Project (Menu) > Clean... > Select project to clean
This also removes invalid errors from Eclipse.
For me Right click on the project --> Maven --> Update project with the "Force Update of Snapshots/Releases" checkmarked worked.
Some times, eclipse's validation causing these errors.
You can disable them by going to Menu>window>preferences>validation and uncheck suspend all validators or disable them one by one for builds.
E.G, every time You build the project eclipse does not validate your files and does not show up those errors.
This worked for me
Delete the Eclipse project from Eclipse interface (do not delete
project contents on disk)
Go to the project's root directory in a
file explorer or terminal
Delete these files: .classpath, .project,
and .settings directory
Back to Eclipse, File -> Import... -> Maven
-> Existing Maven projects
Got the same problem, I deleted the project from my workspace (not on disk), opened the project folder and deleted the files .project, .classpath and the folder named .settings.
Now goto eclipse again, import the same project again and viola my error is gone!
I am having a java project with a ant build file, using this ant file i create an ejb of the project and deploy it on the jboss server.
Now I am planning to use maven and convert this existing project which consist of nearly 28-30 jar's in its class path(jars related to ejb3, hibernate, jboss, etc).
I can easily do it using eclipse i.e right click project goto maven and click Conver to Maven.
A pom.xml is generated and the MavenClassPath Container is also added to the project.
Now I want to know how to get rid of those 28-30 jar's present in the lib folder of the project and in the classpath. i.e. I want my pom.xml handle all the dependencies.
Does Maven provide any mechanism to achieve this goal while converting the project or I have to add all of these jar dependencies one by one manually in the pom.xml file.
The intention of doing this is I want to have common maven remote repository where the jars will be stored and each developer machine will point to it through their maven project.
Thanks
I think you're after a repository manager like Nexus (I use Nexus, it seems to be the most popular http://nexus.sonatype.org/ ).
Nexus can be used as:
A proxy repository (for Maven Central, etc)
A repository for your own releases.
Nexus provides user management for your developers to release builds into the repo.
Developers will then point their Maven settings.xml file to your Nexus repository, and all their dependencies will come from here (Nexus will cache them).
I'm afraid you will have to configure the dependencies individually, but that is a good thing, because you should pay attention to what version ranges you are interested in for each dependency.
Any jars which can't be found in Maven Central, etc, you can add to your own Nexus repository .
Ofcourse there are alternatives to Nexus, but I haven't used any.
HTH
The most important thing i can recommend is to use a Maven Repository Manager (Nexus, Artifactory or Achiva or other..).
Second your pom conversion via Eclipse shows me that you are not using an up-to-date Eclipse nor an up-to-date Maven Plugin for Eclipse. The best thing would be use Eclipse-Indigo (m2e is the newest and greatest).
Furthermore you have to go through all your jar's and add them step by step to you pom (dependencies) and see if your project can be compiled. This should be checked on command line not inside Eclipse.
After you got a working pom.xml file put it into your version control and check if you can remove some of your added dependencies based on transitive dependencies. After that you can finally delete your lib folder.
When I open a POM file and click on the "Dependency Hierarchy" tab at the bottom, it gives me the error, "Project read error". It works with other projects in the same workspace, just not with this one. Any ideas?
EDIT
In response to #Yhn's answer.
Running the compile and package phases outside of Eclipse from the command-line work as expected. It compiles the application and builds the final WAR file.
Eclipse is indeed pointing to the default location of the Maven settings.xml file, so it should be aware of the custom repositories that are defined in it (my company has its own Maven repository).
I can open and edit the POM file from Eclipse, so it must have read/write permissions to the file.
The project is not configured in Eclipse as a Maven project, so I cannot run the package phase from Eclipse (I can only run it from the command-line).
I wonder if it has anything to do with the fact that I was having trouble building the project with Maven 3 because apparently some of the transitive dependencies are configured for Maven 1, which Maven 3 does not support (this is my theory anyway, based on some of the error messages). I can build the project with Maven 2, but I still get messages such as the following:
Downloading: http://dist.codehaus.org/mule/dependencies/maven2/org/codehaus/xfie/bcprov-jdk14/133/bcprov-jdk14-133.pom
[INFO] Unable to find resource 'org.codehaus.xfire:bcprov-jdk14:pom:133' in repsitory mule (http://dist.codehaus.org/mule/dependencies/maven2)
It must be able to find these dependences however, because it downloaded the JARs just fine and can build the application. It seems like the problem is that the dependencies don't have POM files associated with them, which is maybe why they cannot be used with Maven 3. This might also be why I cannot view the Dependency Hierarchy in Eclipse.
EDIT 2
I converted the project to a Maven project by going to "Configure > Convert to Maven Project". When I open the POM file, I see the error:
ArtifactDescriptorException: Failed to read artifact descriptor for woodstox:wst (Click for 140 more)
(woodstox:wst is another transitive dependency of the project). An error appears in the "Markers" view for seemingly every depedency and transitive dependency in my project. However, I can successfully build the project by doing a "Run As > Maven build". (Edit: This might be because this project has no Java source code, but the JARs of the dependencies correctly appear in the final WAR.) The Dependency Hierarchy still gives the same error--"Project read error".
About the "Unable to find resource" messages--but this only appears for a handful of transitive dependencies. The project has many more transitive dependencies, but these messages do not appear for them. It seems like, because the dependencies do not have POM files, that Maven tries to search for them every time the project is built. Is this normal not to have POMs??
How might I go about getting a repo manager? Is this something that would have to be installed on the company's Maven repository or can you install it on your own workstation?
I had this problem with some non-maven jars that I needed to include in my maven project. I put the jars in my local repository using this maven command:
mvn install:install-file -Dfile=/test/gov.nist.xccdf-1.2.jar -DgroupId=gov.nist -DartifactId=xccdf -Dpackaging=jar -Dversion=1.2
Then I referred to them as dependencies in my pom.xml:
<dependency>
<groupId>gov.nist</groupId>
<artifactId>xccdf</artifactId>
<version>1.2</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
This worked fine for a while, but I must have upgraded something in eclipse, and I started getting the error you describe.
The fix is to take them out of the local repository, and redo the install-file asking maven to generate a pom for you:
mvn -DgeneratePom=true install:install-file -Dfile=/test/gov.nist.xccdf-1.2.jar -DgroupId=gov.nist -DartifactId=xccdf -Dpackaging=jar -Dversion=1.2
The command will cause a pom to be generated in the same directory (within your local repo) where the jar is placed.
In recent versions of eclipse maven support, the maven build is still done with maven 2 (if you right-click your pom.xml, choose run as mvn package for example). The dependency analysis is now done with an embedded maven 3 plugin, which doesn't like a dependency that has no pom.xml.
I had the same problem. If you made your project a maven project, you should run:
Right Mouse Click on project | Maven | Update Dependencies or
Right Mouse Click on project | Maven | Update Project Configuration
That worked for me.
Given the information through the comments:
mvn compile/mvn package work through console (I'm assuming outside of eclipse). Based on that, the POM file should be correct and dependencies can be resolved.
However; it could be that eclipse's settings aren't correct. For example, if eclipse has some own maven properties (instead of the default ~/.m2/settings.xml file); I can imagine it to fail resolving dependencies configured in the settings.xml used by maven itself. The settings for this should be in the Eclipse Preferences # Maven > User Settings.
Also make sure that Eclipse can actually read the file (not locked, correct rights, etc).
Should this seem to be correct; can you try to run the mvn goal compile from eclipse? You can do this by right-clicking the project and selecting run as > maven package. That way it should run maven with the same settings as eclipse is using, and might show any additional errors in it's configuration.
--
In response to additional information:
Basically it tells you - when using Maven 2 - that it can't find a dependency resource (in this case bcprov-jdk14) in the given repository (codehaus/mule). When I search that maven module (bcprov-jdk14) I find it in the Maven central repo (through our local nexus) # repo1.maven.org/maven2. Maybe that causes the error you're getting with Maven2?
And as the Maven 3 doc says; for Maven 1.x repo's; you should proxy them through a repo manager that can serve it to you as a maven 2 repository (I believe we do that here too for some repo's through Sonatype Nexus OSS)
ps.: Enabling maven dependency management in eclipse should be enough to be able to use maven run targets; if you would want to test it.
--
Sound like it can be multiple problems... given that the normal maven build works fine, one would think that maven can at least get the artifacts it depends upon and their dependencies... Yet, eclipse doesn't seem to be able to.
Double check if your Eclipse internet connection settings are correct? Since you were talking about a company repo, I'm assuming there will probably also be a proxy (I had to set up my Eclipse to use that one too; though for plugins (see next point)).
Another possibility, from experience, can be a rule-based proxy block on *.pom url requests (our proxy here blocks that to force usage of the local repo manager, how evil and annoying that is :(). You might want to try and open the .pom file it tries to download manually in your browser to see if this is the case (I can't, for example...).
To get the repo set up, you would probably have to ask the one responsible for the repository to add it as a maven2 proxy.
At the very least, it seems Eclipse is having issues getting the dependency poms (which are needed to build the dependency tree) from the internet. You could always try to ask some ICT crew (if they are capable enough...) about it at your company, maybe they have some useful hints.
right click on the project, Maven->Update Project->Tick "Force Update of Snapshots/Releases"
I had the same problem when I added a new dependency to pom.xml without network connection. After this, I had so many problems such as "Missing artifacts", "Missing Descriptor", or "Project Read error". I solved this
delete the bad dependency just added from local repository.
rebuild local index.
re-add the dependency
<properties>
<!-- ********************** -->
<!-- Plugin's properties -->
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.7</java.version>
</properties>
this pom setting worked for me
Usually this happens if there is a typo in the pom that Maven cannot understand and then it throws Project read error. Like in my case I copied a maven dependency snippet and I by passed the version. Instead of typing the actual version # it was getting it dynamically ${asciidoctorj.version} and my pom didn't have this in the properties section. So I got this error. Once I removed that and put a version number it started working.
I had this after copying a local repository folder from another machine. The fix was to go into the repository folder I copied and delete
_remote.repositories along with the 'LastUpdated' files then refresh the Maven dependencies in Eclipse (Alt+F5)
I faced same situation today. In my case it's caused by dependency name in wrong case. E.g.
Project A -> Project B -> Project C
In project B's pm file, I mistakenly specified the dependency artifacts name with "c" in stead of "C".
As in mac os, the files system is case insensitive. so I can build it in command line without detecting this mistake.
In Eclipse it breaks, but it provides very bad error message. In the error list, it says "dependency problem", but the name of dependency is empty. It also can't identify which line in the POM causes the problem.
When try to open "Effective POM" in POM viewer, it will show project read error. In the pop up error dialog box, it will show:
Could not read maven project
java.nio.channels.OverlappingFileLockException
All the messages are useless and misleading.
I finally detected this problem by submit to Jenkins CI after wasted hours of time.
I did maven clean install and the errors were gone
I faced the same issue of "Project read error" while clicking on "Dependency Hierarchy" tab. In my project I had a parent pom and child pom.
Parent pom had a property <appVersion>4.5<appVersion> that was being used in child pom
<version>${appVersion}<version>.
I selected the main project, right click and choose run as maven clean. The console display showed warning that version is using expression but should be a constant. Replacing ${appVersion} with constant value of 4.5 fixed the issue.