Most of the SQL exceptions (e.g. "com.ibm.db2.jcc.c.SqlException: DB2 SQL error: SQLCODE: -545, SQLSTATE: 23513...") are not readable without manual. It would be helpful to get the SQL exception "translated" (in the example above: "constraint x was violated") with a link to the online manual where you can find more informations to the kind of error.
I saw that you have just started with it - just keep it up ;-)
support for it added in 1.2.10-YEARS