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

Message-Driven Beans


A message-driven bean (MDB) is an enterprise bean that is used in Java EE to receive and process messages asynchronously, whatever the messaging style used: point-to-point or publish-subscribe. Any other component—servlets; EJBs; other MDBs; or another Java EE, SE, or non-Java application—can send messages to be processed by message-driven beans. Message-driven beans act as the message listener in JMS.

Message-driven beans are similar to stateful session beans in that:

  • They maintain no conversational state (stateless).
  •  All instances of message-driven beans are equal. Therefore, the application server can maintain a pool of them to serve many requests (messages) concurrently.
  • A single instance of a message-driven bean can serve requests (messages) from different clients.

However, message-driven beans differ from session beans in that:

  • They have no standard interface to access.
  •  They are indirectly accessible by sending message objects to the JMS destination those message-driven...