To debug lock timeout errors, set derby.locks.monitor=true and derby.locks.deadlockTrace=true in derby.properties. This will print the lock table information to the derby.log when the timeout happens. If you also set derby.language.logStatementText=true, then all the statements executed on the system will be written out to the derby.log
H. Aher, P. Shirode, K. Shinde, and A. Jadhav. International Journal on Recent and Innovation Trends in Computing and Communication, 3 (1):
46--51(January 2015)