SQL Error: 1062, SQLState: 23000 : hibernate with concurrence connection - mysql

Question

I've currently two server who are running a same application, this morning they tried to save at the same time an instance of an object 'Rackstatus'.
The result was :
10:23:37,781 WARN [org.hibernate.util.JDBCExceptionReporter]
(XXXX) SQL Error: 1062, SQLState: 23000
10:23:37,783 ERROR [org.hibernate.util.JDBCExceptionReporter]
(XXXX) Duplicate entry '114464' for key
'PRIMARY' 10:23:37,784 ERROR
[org.hibernate.event.def.AbstractFlushingEventListener]
(XXXX) Could not synchronize database state with
session: org.hibernate.exception.ConstraintViolationException: Could
not execute JDBC batch update
my save code :
public void Save(RackStatus stData) {
Session session = null;
session = super.getSession("BANK");
//Create new instance
Transaction trans = session.beginTransaction();
// execute save
session.save(stData);
// do commit
trans.commit();
}
And finally hibernate definition :
<id name="id" type="int">
<column name="id" />
<generator class="assigned"/>
</id>
Any idea ? Thanks.