Book Image

Mastering Hibernate

By : Ramin Rad, Koushik Srinivas Kothagal
Book Image

Mastering Hibernate

By: Ramin Rad, Koushik Srinivas Kothagal

Overview of this book

Hibernate has been so successful since its inception that it even influenced the Java Enterprise Edition specification in that the Java Persistence API was dramatically changed to do it the Hibernate way. Hibernate is the tool that solves the complex problem of Object Relational Mapping. It can be used in both Java Enterprise applications as well as .Net applications. Additionally, it can be used for both SQL and NoSQL data stores. Some developers learn the basics of Hibernate and hit the ground quickly. But when demands go beyond the basics, they take a reactive approach instead of learning the fundamentals and core concepts. However, the secret to success for any good developer is knowing and understanding the tools at your disposal. It’s time to learn about your tool to use it better This book first explores the internals of Hibernate by discussing what occurs inside a Hibernate session and how Entities are managed. Then, we cover core topics such as mapping, querying, caching, and we demonstrate how to use a wide range of very useful annotations. Additionally, you will learn how to create event listeners or interceptors utilizing the improved architecture in the latest version of Hibernate.
Table of Contents (16 chapters)

Fetching strategy

In Java Persistence API (JPA), you can provide a hint to fetch the data lazily or eagerly using the FetchType implementation. However, some implementations may ignore the lazy strategy and just fetch everything eagerly. Hibernate's default to reduce the memory footprint of your application is FetchType.LAZY.


The lazy and eager strategies impact the associated entity. When you set fetch strategy of an associated entity to lazy, Hibernate will not fetch the associated entity until you access the associated entity. You must access the associated entity in the same session where you fetched the parent entity; otherwise, you will encounter an exception. On the other hand, the eager fetch strategy forces Hibernate to retrieve the associated entity when the parent entity is fetched.

As mentioned in the previous chapter, Hibernate offers additional fetch modes in addition to the commonly-used JPA fetch types. Here, we will discuss how they are related and provide an explanation...