13. Caching

<div class="sectionbody">
<div class="paragraph">

At runtime, Hibernate handles moving data into and out of the second-level cache in response to the operations performed by the `Session`, which acts as a transaction-level cache of persistent data.
Once an entity becomes managed, that object is added to the internal cache of the current persistence context (`EntityManager` or `Session`).
The persistence context is also called the first-level cache, and it&#8217;s enabled by default.

</div>
<div class="paragraph">

It is possible to configure a JVM-level (`SessionFactory`-level) or even a cluster cache on a class-by-class and collection-by-collection basis.

</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">

</td>
<td class="content">
<div class="paragraph">

Be aware that caches are not aware of changes made to the persistent store by other applications.
They can, however, be configured to regularly expire cached data.

</div>
</td>
</tr>
</table>
</div>
<div class="sect2">