Hi there,

I was dealing with the same problem.
I'm using latest, 4.7.1 version.
Not sure how this is related but the error is gone after I removed "Archiving artifacts" step.
And it did not matter if I had it before or after "Clover Publisher" step.

I hope this will be helpful to anyone

trbaker: would you able to get the full stack trace for this error?

lukaswoj: thanks for the hint; I suspect that it's either some network error or that Clover unintentionally uses some non-serialisable class

I can investigate it but not sooner than in February. Feel free to grab code from github.com/jenkinsci/clover-plugin to debug it if you wish.

mparfianowicz - sorry but it looks like I lied in my previous comment.
After I removed "Archiving Artifacts" - I still see the same exception being thrown.
The difference, though is that it does no longer causes build to end up with FAILURE state - this is why I missed that fact.
When my build turned from red to green I blindly assumed the exception is gone but apparently this is not the case.

I would happily provide a stack trace but I need guidance on how to produce it. Not sure why in this case stack trace is missing. Within our Jenkins setup, other exceptions that occurs sometimes have full stack trace shown "by default".

I am facing the same issue. Could this be causing the clover xml to not be parsed? The build status is marked as green no matter what the thresh hold is.

I see the XML published by I am not able to see the bullseye coverate report.   

Code changed in jenkins
User: Marek Parfianowicz
Path:
src/main/java/hudson/plugins/clover/CloverPublisher.java
src/main/java/hudson/plugins/clover/slave/GetPathFileCallable.java
http://jenkins-ci.org/commit/clover-plugin/c356a20e9f14da32db36194a2e80e1827ead0c44
Log:
JENKINS-33610: extracted anonymous class to lop-level to get rid of
NoClassDefFoundError: hudson/plugins/clover/CloverPublisher$1'; added more logging

Code changed in jenkins
User: Marek Parfianowicz
Path:
src/main/java/hudson/plugins/clover/CloverPublisher.java
http://jenkins-ci.org/commit/clover-plugin/df5b18dc7a8a667464f522c8f9bc3963d645140f
Log:
JENKINS-33610: println

I had a different exception in the log, but after my change I don't see any errors with remote agents.

I think the change should fix the problem reported by you. I think that because the hudson/plugins/clover/CloverPublisher$1 was an anonymous inner class, so it had a reference to an enclosing class, i.e. the CloverPublisher which does not implement Serializable interface.

And the most probably the CloverPublisher$1 (now renamed to GetPathFileCallable, which implements SlaveToMasterFileCallable) was called by the FileCallableWrapper mentioned in the bug description.

Fix will be delivered in 4.8.1+