Maintaining the history of an object

In the previous recipe, we used the versioning feature of hibernate to check how many times a particular record has been modified. This is a good feature; however, it gives us just a number. Versioning does not store the modified data anywhere. So, it's hard to find out the previous state of the object before the modification.

As a solution to this, hibernate provides another project called Envers.

Envers helps us maintain the history of the database and it keeps track of the modifications in the database table rows. For this to work, we have to change the configuration in the POJO and configuration (.cfg.xml) files.

To configure Envers with hibernate, we need JAR files in our project. You can use the following Maven dependency for the Maven-based project:

<dependency>
  <groupId>org.hibernate</groupId>
  <artifactId>hibernate-envers</artifactId>
  <version>4.3.10.Final</version>
</dependency>

Once we configure...