Dependency injection

Dependency injection is a technique for supplying external dependencies to a Java class. Java EE 5 introduced dependency injection via the @Resource annotation, however, this annotation is limited to injecting resources such as database connections, JMS resources, and so on. CDI includes the @Inject annotation, which can be used to inject instances of Java classes into any dependent objects.

JSF applications typically follow the Model-View-Controller (MVC) design pattern. As such, often some JSF managed beans take the role of controllers in the pattern, while others take the role of the model. This approach typically requires the controller managed bean to have access to one or more of the model-managed beans. CDI's dependency injection capabilities make injecting beans into one another very simple, as illustrated in the following example:

package net.ensode.javaee8book.cdidependencyinjection.ejb; 
 
import java.util.logging.Logger; 
import javax.inject.Inject; 
import...