The test cases CompressTableTest.testConcurrentInvalidation() and TruncateTableTest.testConcurrentInvalidation() fail intermittently with errors such as:
ERROR XSAI2: The conglomerate (2,720) requested does not exist.
The problem has been analyzed in the comments on
DERBY-4275, and a patch attached to that issue (invalidation-during-compilation.diff) fixes the underlying race condition. However, that patch only works correctly together with the fix for DERBY-5161, which was backed out because it caused the regression DERBY-5280.