11.7.6. Roll Back a Transaction

Call the rollback() method on the UserTransaction.

 
@Inject
private UserTransaction userTransaction;

public void updateTable(String key, String value)
    EntityManager entityManager = entityManagerFactory.createEntityManager();
    try {
        userTransaction.begin():
        <!-- Perform some data manipulation using entityManager -->
          ...
          // Commit the transaction
        userTransaction.commit();
    } catch (Exception ex) {
        <!-- Log message or notify Web page -->
        ...
        try {
            userTransaction.rollback();
        } catch (SystemException se) {
            throw new RuntimeException(se);
        }
        throw new RuntimeException(e);
    } finally {
        entityManager.close();
    }
}

If you use Container Managed Transactions (CMT), you do not need to manually roll back the transaction.