What is the role of caching mechanism in Hibernate and why is it used?

The caching mechanism in Hibernate is used to improve performance when working with a database. It allows storing objects in memory that have already been loaded, so that repeated requests for the same data do not require additional SQL queries.

Hibernate supports two levels of cache:

• First-level cache (Session Cache) — associated with a Hibernate session. All objects loaded within a session are stored in this cache. When the same object is requested again within the same session, no database query is performed.
• Second-level cache — shared across multiple sessions and allows caching data between sessions. It requires additional configuration and the use of cache providers (e.g., Ehcache).

Using cache reduces the load on the database, decreases application response time, and increases overall performance.