Two tests in jena-jdbc-driver-tdb (TestTdbDiskResultSets and TestTdbDiskConnection) create a lot of temporary data while running, in the form of on-disk TDB datasets. If those datasets don't get deleted promptly as they are not longer needed, they can fill up the disk and blow out the build. This seems to be happening both on Windows and Mac boxes. In the Windows case, there is a known problem with Java being unable to release files once they have been memory-mapped. But for Macs, it should be possible to smarten up the test framework a bit to ensure that filesystem resources are getting released promptly.