DB errors + hibernate

[Vadim javasd]

Hi!
I create desktop application. I work with database using hibernate and Netbeans. For example method which delete object from database.

public  static boolean deleteOneEntity(Object obj){
        boolean statusOperation=true;
         Session session = null;
         try {
             session = HibernateUtil.getSessionFactory().getCurrentSession();
             session.beginTransaction();
             session.delete(obj);
             session.flush();
             session.getTransaction().commit();
         } catch (Exception e) {
             JOptionPane.showMessageDialog(null, e.getMessage(), "Transaction error", JOptionPane.OK_OPTION);
             statusOperation = false;
             } finally {
                 if (session != null && session.isOpen()) {
                     session.close();
                 }
               }
             return statusOperation;
     } 

Tell me please how to handle errors when working with a database to display user messages like: "The object has already been removed" or "Record already exists" or "No database connection".