What is CDI and EJB?

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So, while CDI aims at modularization and separation of concerns, EJB is adding container services. When a bean is defined as EJB (by declaring them as @Stateless or @Stateful), the container takes care of transaction handling, security, concurrency and pooling.

What is CDI bean?

A CDI bean is a POJO, plain old java object, that has been automatically instantiated by the CDI container, and is injected into all, and any qualifying injection points in the application. The CDI container initiates the bean discovery process during deployment.

What is Beans xml for?

The beans. xml file is the bean archive descriptor for CDI applications. It can be used for any CDI compliant container, such as Weld which is included in WildFly application server.

Where do I put beans xml?

The bean archive descriptor beans. xml should be located at META-INF/beans. xml or WEB-INF/beans.

What is the difference between @EJB and @inject?

The @EJB is used to inject EJB’s only and is available for quite some time now. @Inject can inject any managed bean and is a part of the new CDI specification (since Java EE 6). In simple cases you can simply change @EJB to @Inject .

What is inject annotation?

@Inject annotation is a standard annotation, which is defined in the standard “Dependency Injection for Java” (JSR-330). Spring (since the version 3.0) supports the generalized model of dependency injection which is defined in the standard JSR-330.

How does CDI injection work?

CDI (Contexts and Dependency Injection) is a standard dependency injection framework included in Java EE 6 and higher. It allows us to manage the lifecycle of stateful components via domain-specific lifecycle contexts and inject components (services) into client objects in a type-safe way.

What is context in CDI?

A context in CDI is some span during execution of your program when contextual objects can be used. It defines when CDI container creates, destroys and how it links instances of those objects together. Non-contextual objects are those that are not tied to any CDI context.

What is CDI Java?

Overview. CDI (Contexts and Dependency Injection) is a standard dependency injection framework included in Java EE 6 and higher. It allows us to manage the lifecycle of stateful components via domain-specific lifecycle contexts and inject components (services) into client objects in a type-safe way.

What is XML configuration?

An XML configuration file groups configurations into one or more elements. Normally, each is given a unique name, using the “name” attribute. It is also permissible to include an element without a name attribute (the “unnamed” application element).

Do you need beans xml?

Yes beans. xml file is required by CDI 1.1. The places where to put them may vary depending upon your packaging style. So if you are going to have war then beans.

How do you inject EJB beans?

Steps to Use @EJB public class LibraryMessageBean implements MessageListener { //dependency injection on field. @EJB LibraryPersistentBeanRemote libraryBean; } public class LibraryMessageBean implements MessageListener { LibraryPersistentBeanRemote libraryBean; //dependency injection on method. @EJB(beanName=”com.

What is the use of Bean XML in CDI?

For example, in CDI, you can use beans.xml to enable interceptors (disabled by default) and define interceptor priority. So the bean descriptor complements the metadata that is provided in the Java language syntax. Is the beans.xml file required?

What is CDI in Java EE?

The beans.xml file is used by CDI to instruct the Java EE-compliant server that the project is a module containing CDI beans. Java EE 6 Web supports CDI 1.0 and the generated beans.xml file specifies CDI 1.0 as the version. If you specify Java EE 7 Web as the Java EE version, CDI 1.1 is enabled by default and the beans.xml file is not required.

Where can I find the beans XML file?

How to scan for annotated beans in a CDI Container?

Starting from CDI 1.1, beans.xml is no longer mandatory. And the scanning is as follow : Omitting beans.xml, or setting bean-discovery-mode=”annotated”, makes the archive an implicit archive. In this case, the container will scan for beans with annotated scope types.