Hi,i am running a java project on tomcat 7 and its runs well when i am in the office,after i come back next day it shows "jdbc roll back error" ,when i restart tomcat it works fine again,but its happening everyday.I tried to trace the problem through logs but nothing was there ,so i write a shell script for restarting tomcat automatically for every 5 hrs.I tested it but again when i come back next day morning same error appears.I am clueless regarding this error.Any help would be greatly appreciated.

Details:
Server :RHEL 5
JDk : 7
Tomcat :7
Mysql : 5.5
JDBC : Hibernate

Thanks in advance..