When you create session using SessionFactory.openSession(), no transaction is created, so your operations are executed outside of transaction context. In order to see your changes, you have to start a new transaction, or perform your operations as a part of ongoing transaction. From documentation:
A typical transaction should use the following idiom:
Session sess = factory.openSession();
Transaction tx;
try {
tx = sess.beginTransaction();
//do some work
...
tx.commit();
}
catch (Exception e) {
if (tx!=null) tx.rollback();
throw e;
}
finally {
sess.close();
}