Handling Exceptions

Most exceptions in queries are database exceptions, resulting from a failure in the database operation (see Database Exceptions (4002 – 4018) section in the TopLink Exception Reference chapter for more information). Write operations can also throw an OptimisticLockException on a write, update, or delete operation in applications that use optimistic locking. To catch these exceptions, execute all database operations within a try-catch block:

{
    try
    {
        Vector employees = session.readAllObjects(Employee.class); 
    } 
        catch (DatabaseException exception)
    {
        // Handle exception 
    }
}

See Chapter 14, "TopLink Workbench Error Reference" for more information about exceptions in a TopLink application.