If deadlocks occur frequently in your multi-user system with a particular application, you might need to do some debugging.
Derby provides a class to help you in this situation, org.apache.derby.diag.LockTable. You can also set the property derby.locks.deadlockTrace to dump additional information to the derby.log file about any deadlocks that occur on your system. See the Tuning Guide for more information on this property. For information, see the Java DB Server and Administration Guide.