Hey Dan, Given the symptoms you mention, I think you may be hitting the same issue with your concurrent build as we did a while ago (and which has been reported as https://issues.apache.org/jira/browse/MNG-5960).
Basically, (based on some debugging I did for our build,) having some aggregate plugin running in anything else than your root project may cause this to happen in a multi-threaded build. In our case, it was the default behaviour of the maven-javadoc-plugin. In short, it boils down to the aggregate plugin resolving compile-scope dependencies for _all_ projects in the reactor, which may possibly overwrite already resolved test-scope dependencies for currently building projects; resulting in classpath issues (usually) no longer being able to find junit. I don't know if there is an easy way to find aggregate plugins other than looking into their mojo source code; so maybe someone else on this list can help you with that.. Good luck! -- Fabian On Fri, 2017-05-05 at 00:51 -0700, Dan Tran wrote: Hi Lately, my build randomly fails with java.lang.NoClassDefFoundError: org/junit/runner/notification/RunNotifier at surefire My environment consists of * 200+ modules running with --builder smart -T 4 * surefire 2.19.1 and 2.20, maven 3.3.9 and 3.5 * Build runs on Sles12SP2 with OpenJDK8 Stack Overflow has a similar issue back in 2014 Any suggestion helping to trouble shoot this issue is greatly appreciated Thanks -Dan
