If you are using Intellij go to Settings -> Build, Execution, Development -> Compiler -> Annotation Processors -> Processor Path
And tick the Obtain processors from project classpath radio button
In my case Intellij was using the processor path (the 2nd option) which is the default option when you enable Annotation processors but for some reason Intellij was including jars prefixed with unknown instead of including the jars used in the project. but using the 1st option Intellij will use the maven configuration instead of it's own classpath resolver
