Error opening Maven POM file dependency hierarchy in Eclipse - "Project read error"

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.

1. 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.
2. 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).
3. I can open and edit the POM file from Eclipse, so it must have read/write permissions to the file.
4. 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?

Solution 1:

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.

Solution 2:

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.

Solution 3:

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.

Solution 4:

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

1. delete the bad dependency just added from local repository.
2. rebuild local index.
3. re-add the dependency