Spring vs. EJB 3

This article would overview the differences between Spring Framework and EJB 3

EJB 3.0

• EJB 3.0 is a specification.
• EJB is an architecture
• The EJB 3.0 framework is a standard framework defined by the Java Community Process (JCP) and supported by all major J2EE vendors. Open source and commercial implementations of pre-release EJB 3.0 specifications are already available .

Spring Framework

• Spring is an implementation.
• Spring is application framework
• The Spring framework is a popular but non-standard open source framework. It is primarily developed by and controlled by Interface21 Inc. Spring can work standalone or with existing application servers.

EJB 3.0 Advantages

• EJB 3.0 specification horroble old entity beans have been replaced with the JPA
• Deal with transactions and both succeed modularizing this functionality in a way that it doesn't clutter business logic
• Tune the transaction propagation levels via annotations
• Support state management via stateful session beans,
• Support injection of primitive types, allows injecting EJB's
• Supports AOP using interceptors
• Brings a basic implementation of component management

Spring Framework Advantages

• Integrates with many popular persistence frameworks including JDBC, Hibernate, JDO, iBatis and JPA.
• Transaction demarcation, propagation, and isolation are all declared through its AOP.
• Support state management via prototype beans and also request, session, and global session scoping
• Support injection of any type, allows injection of any domain objects using the features of AspectJ
• Suppotrs AOP by tightly integrating with AspectJ with all of it's features
• Spring 2.0 offers a lot more power and customization, but the use of AspectJ actually makes the hard to learn

Spring Framework Disadvantages

• The idea of annotations was to stop work with XML - Deploymenet Descriptor files which were in EJB 2.1, but Spring encourage a lot the use of XML for dependency injection
• Refresh the Spring load data is impossible, if you change something in the configuration you need to restart the Application Server.

You can integrate Spring and EJB 3 technologies to take advantage of their relative strengths and weaknesses, In Spring and EJB 3 there are a lot of duplication in the compoments you can choose the best of this technologies to use in you application.