You can find the full source code for this website in the Seam package in the directory /examples/wiki. It is licensed under the LGPL.
When a Weld-enabled application is deployed on an application server or a web server, proxy classes for beans implementing interfaces or extending classes contained in common libraries are loaded in the class loader (CL) for that library, not the thread context class loader (TCCL). This means that these proxy classes will not be removed from the server when the application is undeployed.
The reason for this approach is to support the use of package scoped classes and members of classes which need to be proxied as beans. Thus the TCCL is not used for the proxy classes generated by Weld.
One way to prevent this problem is to simply deploy those libraries with your application. In this scenario, those classes are loaded in a CL associated with the application and will thus be removed when the application is undeployed.