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)

Cache structure

You may not have realized but you have already been using at least the first-level cache that is managed by the Hibernate session. In addition to the first-level cache, Hibernate also offers the ability to set up a second-level cache. Furthermore, it's possible to cache the result of queries that are frequently executed, which are known as query caches. Let's discuss these here.

Cache scope

Before we discuss cache levels, we need to understand the scope of a cached entity:

  • A cached entity may only span the life of a transaction; this means the cached entity is only available for the thread that owns the persistence unit of work.

  • The next wider scope is the process, for example, your web application. An entity may be cached as long as the web application is running. In this case, the cached entity may be shared by multiple threads, perhaps even concurrently.

  • Finally, if you are in a clustered environment, entities can be cached on every node of the cluster. Clearly, when an entity...