I know it's possible to map several classes to a single table using
component element, but i want to do the opposite : map several
tables to one class. i know it can be achieved with joined style
inheritance, but i want to join 2 tables that don't map to classes
with inheritance relations. is it possible ?
thanks a lot.

See http://www.hibernate.org/hib_docs/v3/reference/en/html_single/#mapping-declaration-join

wouldn t it be much easier to work on a table view?
(or am i completely wrong?)

Hibernate is certainly capable of doing so, although if you plan to update your entities (specifically, CREATE UPDATE or DELETE), the view must support this (which depends on your database's capabilities). The documentation states that views (as expected) are transparent to hibernate at the database level, and appear to be tables.

If you have the option of creating a VIEW for your entity, then that may certainly be the option you'll wish to choose. It's really a matter of taste. However, if you don't have the option of creating a VIEW (for whatever reasons), Hibernate can still support your requirements through a join mapping.

Your database doesn't have to support materialized views if you can create a trigger to intercept DML to the view and split it up into operations on the view's component tables.