Since you have assign the task to learn Hibernate it means you are going to work on database driven application. Most probably the web application.
Let me explain you about Hibernate.
Hibernate is a technology for saving your data into database without writing the JDBC code.
From you Java program you will issue the command to save the Entity (Java object), and hibernate will generate the query and save the data into database. Its so simple to save data now.
There are lots of benefits of Hibernate but most important is that it handles all the JDBC stuff and saves huge development time.
Check the tutorial What is Hibernate in Java?.