code: @Override
      public final void persist(Object e)
      {
          checkClosed();
          checkTransactionNeeded();
          try
          {
              getPersistenceDelegator().persist(e);
          }
          catch (Exception ex)
          {
              // onRollBack.
              doRollback();
              throw new KunderaException(ex);
          }
      }
docs: Make an instance managed and persistent.
  
  @param entity
  @throws EntityExistsException
  if the entity already exists. (If the entity already exists,
  the EntityExistsException may be thrown when the persist
  operation is invoked, or the EntityExistsException or another
  PersistenceException may be thrown at flush or commit time.)
  @throws IllegalArgumentException
  if the instance is not an entity
  @throws TransactionRequiredException
  if invoked on a container-managed entity manager of type
  PersistenceContextType.TRANSACTION and there is no
  transaction