Group items tagged

Pros and Cons of JEE and Spring

Advantages of JEE

set of standard specifications, thus it is vendor-independent

testing is possible!

Lightweight application servers and frameworks such as Arquillian arrived

reduces the test setup code by

@Inject

CDI managed beans. The @EJB annotation is removed and @Inject is used instead

Annotating the boundary (Cart) with the @Named annotation makes the Cart immediately visible for expression language (EL) expressions in JSP and JSF

@Named annotation takes the simple name of the annotated class, puts the first character in lowercase, and exposes it directly to the JSF pages (or JSP). The Cart bean can be accessed directly, without any backed or managed beans, by the JSF pages: <h:commandButton value="Check out!" action="#{cart.checkout}" />

If there is a need for abstraction, the class can be turned into an interface (or abstract class)

local implementation (with CDI events

@Inject Event<String> event;

event.fire("Order proceeded!");

remote implementation:

javax.enterprise.event.Event belongs to the CDI-implementation

class Event can be considered to be a lightweight alternative to the java.beans.PropertyChangeSupport class

@Inject Event<String> event;

event.fire("Order proceeded!");

event can be received by any managed bean and also by EJB beans

provide a method with a single @Observes annotated parameter

@Observes String event

there is no real event, just the payload:

The during attribute in the @Observes annotation allows you to select in which transactional phase the event gets delivered. The default setting is IN_PROGRESS, which causes an immediate event delivery regardless of the transaction outcome. The AFTER_SUCCESS configuration causes the delivery to occur only after successful transaction completion

Although CDI events work only inside a single process (in the default case, CDI is extensible), they are perfectly suitable for decoupling packages from modules

The method checkout() starts a transaction that gets "reused" by the OrderSystem and CustomerNotification session beans

ordering.placeOrder(); notifier.sendNotification();

EJB beans cannot be directly exposed to JSF or JSP without a little help from CDI

The discussion whether or not to use Spring vs. Java EE for new enterprise Java applications is a no-brainer

Why migrate?

since then fallen a prey to the hungry minds of Venture Capitalists and finally into the hands of a virtualization company called VMware

While the different companies and individuals behind the Spring framework have been doing some work in the JCP their voting behavior on important JSRs is peculiar to say the least

outdated ORM solution like JDBC templates

some developers completely stopped looking at new developments in the Java EE space and might have lost track of the current state of technology

size of the deployment archive

fairly standard Java EE 6 application will take up about 100 kilobytes

comparable Spring application weighs in at a whopping 30 Megabytes!

Lightweight

Firing up the latest JBoss AS 7 Application Server from scratch and deploying a full blown Java EE 6 application into the server takes somewhere between two and five seconds on a standard machine. This is in the same league as a Tomcat / Spring combo

Dependency injection

Java EE 6, the Context and Dependency Injection (CDI) specification was introduced to the Java platform, which has a very powerful contextual DI model adding extensibility of injectable enterprise services

Aspect Oriented Programming

“AOP Light” and this is exactly what Java EE Interceptors do

common pitfall when taking AOP too far is that your code might end up all asymmetric and unreadable. This is due to the fact that the aspect and its implementation are not in the same place. Determining what a piece of code will do at runtime at a glance will be really hard

Testing

With Arquillian we can get rid of mocking frameworks and test Java EE components in their natural environment

Tooling

capabilities comparison matrix below to map Spring’s technology to that of Java EE

Capability Spring JavaEE Dependency Injection Spring Container CDI Transactions AOP / annotations EJB Web framework Spring Web MVC JSF AOP AspectJ (limited to Spring beans) Interceptors Messaging JMS JMS / CDI Data Access JDBC templates / other ORM / JPA JPA RESTful Web Services Spring Web MVC (3.0) JAX-RS Integration testing Spring Test framework Arquillian *