The purpose of this chapter was to expose the internals of Hibernate as they relate to session and entity. This should help you understand Hibernate better, design and write more elegant code, and when you encounter errors, understand the error messages clearly.

You will see a lot more sample code in later chapters, but in this chapter, we focused more on understanding Hibernate, and less on samples.

We learned about session and its behavior in various contexts. We also learned about entity, explored its lifecycle, and also learned about map types, which is a dynamic entity. Furthermore, the discussion on entity identity is very important and deserves careful attention. As discussed in this chapter, Hibernate offers a rich set of features, which are not available in JPA. We will see more of them in future chapters. Finally, we talked about proxy objects and batch processing.

This chapter is the heaviest in content. In the following chapters, we will focus on specific topics and explore different ways to accomplish certain objectives using Hibernate. The next chapter covers mapping concepts, and you will take a look at how basic and advanced mapping can fill the gap between objects and relations.