Sun Java System Application Server Enterprise Edition 8.2 Developer's Guide

No Support for lock-when-loaded on Sybase and DB2

The lock-when-loaded consistency level is implemented by placing update locks on the data corresponding to a bean when the data is loaded from the database. There is no suitable mechanism available on Sybase and DB2 databases to implement this feature. Therefore, the lock-when-loaded consistency level is not supported on Sybase and DB2 databases.