Book Image

Developing Middleware in Java EE 8

Book Image

Developing Middleware in Java EE 8

Overview of this book

Middleware is the infrastructure in software based applications that enables businesses to solve problems, operate more efficiently, and make money. As the use of middleware extends beyond a single application, the importance of having it written by experts increases substantially. This book will help you become an expert in developing middleware for a variety of applications. The book starts off by exploring the latest Java EE 8 APIs with newer features and managing dependencies with CDI 2.0. You will learn to implement object-to-relational mapping using JPA 2.1 and validate data using bean validation. You will also work with different types of EJB to develop business logic, and with design RESTful APIs by utilizing different HTTP methods and activating JAX-RS features in enterprise applications. You will learn to secure your middleware with Java Security 1.0 and implement various authentication techniques, such as OAuth authentication. In the concluding chapters, you will use various test technologies, such as JUnit and Mockito, to test applications, and Docker to deploy your enterprise applications. By the end of the book, you will be proficient in developing robust, effective, and distributed middleware for your business.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Performing CRUD operations


In the following sections, we are going to learn how to use JPA for performing the four basic data access operations: creating, retrieving, updating, and deleting entities.

Managed versus detached entities

One of the most important concepts to understand about the JPA framework is that every entity has a state at each point during runtime. An entity can be in one of two states:

  • Managed: A managed entity is one that is synchronized with the database; any changes in the entity state will be reflected in the database. In other words, the persistence provider is tracking a managed entity state, and keeps updating the database with any changes that occur to its state.
  • Detached: A detached entity is one that is not synchronized with the database; any changes in the entity state will not be reflected to the database. The persistence provider does not track any changes that occur to the entity.

As you will see later, by performing the different CRUD operations supported by...