When 2 maven projects (where job B depends on job A) are built simultaneously, we often encounter this error in job B, which leads to a failed build without apparent reason:
This happens because job B tries to access a jar deployed by job A while it is being written.
This occurs rather frequently here, especially when an SVN commit triggers several parallel maven builds (directly or indirectly).
Jenkins is usually aware that the jobs depend on each other, but there are situations where both are running simultaneously nevertheless, e.g. when B is triggered just before A.
I think the problem could be solved by locking files in the local maven repo while they are being written, or maybe through some semaphore to synchronize access to .m2.