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Chapter 18. Application servers and environments supported by Weld

18.1. Using Weld with JBoss AS
18.2. GlassFish
18.3. Servlet containers (such as Tomcat or Jetty)
18.3.1. Tomcat
18.3.2. Jetty
18.4. Java SE
18.4.1. CDI SE Module

If you are using JBoss AS 5.2, no additional configuration is required to use Weld (or CDI for that matter). All you need to do is make your application a bean bean archive by adding META-INF/beans.xml to the classpath or WEB-INF/beans.xml to the web root!

Unfortunately, you can't use Weld with earlier versions of JBoss AS since they are missing key libraries. If you want to learn how to upgrade the built-in support on JBoss AS 5.2, then read on.

Upgrading the Weld add-on is easy. The Weld distribution has a build that can take care of this task for you in a single command. First, we need to tell Weld where JBoss AS is located. Create a new file named in the examples directory of the Weld distribution and assign the path of your JBoss AS installation to the property key jboss.home, as follows:


Now we can install the Weld deployer from the jboss-as directory of the Weld distribution:

$> cd jboss-as
$> ant update

Weld is also built into GlassFish from V3 onwards. Since GlassFish V3 is the Java EE 6 reference implementation, it must support all features of CDI. What better way for GlassFish to support these features than to use Weld, the JSR-299 reference implementation? Just package up your CDI application and deploy.

While JSR-299 does not require support for servlet environments, Weld can be used in any servlet container, such as Tomcat 6.0 or Jetty 6.1.

Weld should be used as a web application library in a servlet container. You should place weld-servlet.jar in WEB-INF/lib in the web root. weld-servlet.jar is an "uber-jar", meaning it bundles all the bits of Weld and CDI required for running in a servlet container, provided for your convenience. Alternatively, you could use its component jars:

You also need to explicitly specify the servlet listener (used to boot Weld, and control its interaction with requests) in WEB-INF/web.xml in the web root:


In addition to improved integration of the Enterprise Java stack, the "Contexts and Dependency Injection for the Java EE platform" specification also defines a state of the art typesafe, stateful dependency injection framework, which can prove useful in a wide range of application types. To help developers take advantage of this, Weld provides a simple means for being executed in the Java Standard Edition (SE) environment independently of any Java EE APIs.

When executing in the SE environment the following features of Weld are available:

Weld provides an extension which will boot a CDI bean manager in Java SE, automatically registering all simple beans found on the classpath. Application developers need not write any bootstrapping code. The entry point for application code is a simple bean which observes the special ContainerInitialized event provided by this extension. The command line parameters can be injected using either of the following:

@Inject @Parameters List<String> params;

@Inject @Parameters String[] paramsArray; // useful for compatability with existing classes

Here's an example of a simple CDI SE application:


public class HelloWorld
   @Inject @Parameters List<String> parameters;
   public void printHello(@Observes ContainerInitialized event) {
       System.out.println("Hello " + parameters.get(0));

CDI SE applications can be bootstrapped by running the StartMain class like so:

java <args>

If you need to do any custom initialization of the CDI bean manager, for example registering custom contexts or initializing resources for your beans you can do so in response to the AfterBeanDiscovery or AfterDeploymentValidation events. The following example registers a custom context:

public class PerformSetup {

   public void setup(@Observes AfterBeanDiscovery event) {
      event.addContext( ThreadContext.INSTANCE );