After learning JDBC, I was proud of myself. I could connect to a database, run queries and read the results. Then I built a real project with 12 tables, and my code filled up with the same pattern again and again: open a connection, prepare a statement, set five parameters, run it, loop over a ResultSet , copy each column into an object, close everything. Changing one column name meant hunting through dozens of SQL strings.

That's the problem ORM tools were invented to solve, and Hibernate is the most famous one in Java. You describe how your classes map to tables once, and Hibernate writes and runs the SQL for you.

In this post, we'll learn what ORM is and which problem it solves, its pros and cons, what Hibernate is and how it works, how to use it with and without Maven (using PostgreSQL), the common methods you'll use, how Hibernate relates to Jakarta Persistence (JPA) , and a step-by-step example in the Spring Framework .…