Consider the attached project, which builds in Maven 2.1. The "parent" project has a dependencyManagement section that declares the version of JUnit as 3.8.1. The "child" project has duplicate dependency entries for junit; neither one declares a version.
Maven 3 generates a very misleading error message; it took a long time for me to figure out the real cause of the problem.
[INFO] Scanning for projects...
[ERROR] The build could not read 1 project -> [Help 1]
[ERROR] The project bug:child:1.0-SNAPSHOT (C:\Temp\scratch\parent\child\pom.xml) has 2 errors
[ERROR] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: junit:junit:jar -> null vs null
[ERROR] 'dependencies.dependency.version' is missing for junit:junit:jar
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http:
I expected an error more like:
'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: junit:junit:jar -> duplicate declaration of 3.8.1
That would have been MUCH more helpful.