{"id":13627,"date":"2013-06-04T22:00:15","date_gmt":"2013-06-04T19:00:15","guid":{"rendered":"http:\/\/www.javacodegeeks.com\/?p=13627"},"modified":"2019-12-09T21:14:18","modified_gmt":"2019-12-09T19:14:18","slug":"java-ee-cdi-dependency-disambiguation-example","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/2013\/06\/java-ee-cdi-dependency-disambiguation-example.html","title":{"rendered":"Java EE CDI dependency disambiguation example"},"content":{"rendered":"

In this tutorial we shall show you how to avoid dependency disambiguation in CDI beans. In CDI we can achieve dependency injection for multiple implementations of an interface to different clients in an application. The problem of dependency disambiguation is how a client can call a specific implementation among different ones, without any errors occurring.<\/p>\n

To see how we can avoid dependency disambiguation when injecting beans to an application we will create a simple service. We will create two implementations of the service and then we will inject both implementations in a servlet in our application. We will make use of the @Qualifiers<\/code>, as will be explained below.<\/p>\n

Our preferred development environment is Eclipse<\/a>. We are using Eclipse Juno (4.2) version, along with Maven<\/a> Integration plugin version 3.1.0. You can download Eclipse from here<\/a> and Maven Plugin for Eclipse from here<\/a>. The installation of Maven plugin for Eclipse is out of the scope of this tutorial and will not be discussed. Tomcat 7<\/a> is the application server used.<\/p>\n

Let’s begin,<\/p>\n

1. Create a new Maven project<\/h2>\n

Go to File -> Project ->Maven -> Maven Project.<\/p>\n

\"New-Maven-Project\"<\/a><\/p>\n

In the “Select project name and location” page of the wizard, make sure that “Create a simple project (skip archetype selection)” option is unchecked<\/strong>, hit “Next” to continue with default values.<\/p>\n

\"new<\/a><\/p>\n

Here the maven archetype for creating a web application must be added. Click on “Add Archetype”<\/strong> and add the archetype. Set the “Archetype Group Id” variable to \"org.apache.maven.archetypes\"<\/code>, the “Archetype artifact Id” variable to \"maven-archetype-webapp\"<\/code> and the “Archetype Version” to \"1.0\"<\/code>. Click on “OK”<\/strong> to continue.<\/p>\n

\"maven-archetype-webapp\"<\/a><\/p>\n

In the “Enter an artifact id” page of the wizard, you can define the name and main package of your project. Set the “Group Id” variable to \"com.javacodegeeks.snippets.enterprise\"<\/code> and the “Artifact Id” variable to \"cdibeans\"<\/code>. The aforementioned selections compose the main project package as \"com.javacodegeeks.snippets.enterprise.cdibeans\"<\/code> and the project name as \"cdibeans\"<\/code>. Set the “Package” variable to \"war\"<\/code>, so that a war file will be created to be deployed to tomcat server. Hit “Finish” to exit the wizard and to create your project.<\/p>\n

\"newcdiproject1\"<\/a>

<\/div> <\/div><\/p>\n

The Maven project structure is shown below:<\/p>\n

\"newcdiproject2\"<\/a><\/p>\n