I have the following scenario:

1. The object X is loaded.

2. Same changes were made in object X.

3. I need to perform a query to validate the object X.

4. If the object X was valiad, then make persistent.

The problem is that when I do the query, the object X is saved. How can I query without save before?

Can you post your model so it is easy to understand what is the problem

Before executing HQL-queries, hibernate flushes the session, so the object is updated within this transaction but not comitted, yet.
You could do your validation in another transaction, but you should probably just rewrite your validation-query, so that it does "recognize" the object X.