Enterprise JavaBeans 3

EJB overview

In very straightforward terms, Enterprise JavaBeans (EJB) is a platform for building portable, reusable, and scalable business applications using the Java programming language. Since its initial incarnation, EJB has been touted as a component model or framework that lets you build enterprise Java applications without having to reinvent services such as transactions, security, automated persistence, […]

Understanding EJB types

If you’re like most developers, you always have a tight deadline to meet. Most of us try to beg, borrow, or steal reusable code to make our lives easier. Gone are those days when developers had the luxury to create their own infrastructure when building a commercial application. While several commercial and open source frameworks […]

Getting inside EJB

When you build a simple Java class, you need a Java Virtual Machine (JVM) to execute it. In a similar way (as you learned in the previous section) to execute session beans and MDBs you need an EJB container, and to run your entities you need a persistence provider. In this section we give you […]

Renaissance of EJB

Software is organic. Much like carbon-based life forms, software grows and evolves. Features die. New features are born. Release numbers keep adding up like the rings of a healthy tree. EJB is no exception to the rule of software evolution. In fact, as far as technologies go, the saga of EJB is more about change […]

New features: simplifying EJB

There are three primary sources of complexities in EJB 2: the heavyweight programming model, direct use of the Java Naming Directory Interface (JNDI), and a verbose XML deployment descriptor. Three primary techniques in EJB 3 eliminate these sources of complexity: metadata annotations, minimal deployment descriptors, and dependency injection. In the following sections, we introduce all […]

Introducing the ActionBazaar application (EJB 3)

ActionBazaar is a simple online auctioning system like eBay. Sellers dust off the treasures hidden away in basement corners, take a few out-of-focus pictures, and post their item listings on ActionBazaar. Eager buyers get in the competitive spirit and put exorbitant bids against each other on the hidden treasures with the blurry pictures and misspelled […]

Building business logic with session beans (EJB 3)

Session beans are meant to model business processes or actions, especially as perceived by the system user. This is why they are ideal for modeling the bidding and ordering processes in our scenario. Session beans are the easiest but most versatile part of EJB. Recall that session beans come in two flavors: stateful and stateless. […]

Messaging with message-driven beans (EJB 3)

Just as session beans process direct business requests from the client, MDBs process indirect messages. In enterprise systems, messaging has numerous uses, including system integration, asynchronous processing, and distributed system communication. If you’ve been working on enterprise development for some time, you’re probably familiar with at least the idea of messaging. In the most basic […]

Persisting data with EJB 3 JPA

The Java Persistence API (JPA) is the persistence-tier solution for the Java EE platform. Although a lot has changed in EJB 3 for session beans and MDBs, the changes in the persistence tier have truly been phenomenal. In fact, other than some naming patterns and concepts, JPA has very little in common with the EJB […]

Getting to know session beans (EJB 3)

A typical enterprise application will have numerous business activities or processes. For example, our ActionBazaar application has processes such as creating a user, adding an item for auctioning, bidding for an item, ordering an item, and many more. Session beans can be used to encapsulate the business logic for all such processes. The theory behind […]

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