Maven项目：无法读取工件描述符

Question

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

Answer 1

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.