experimenting with JBoss 7 quickstart helloworld tutorial

[mperdikeas]

I am coming from a Tomcat / JSF background so I did a little experimentation with the quickstart helloworld tutorial.

Specifically I was curious as to the need for the beans.xml file which basically defines namespaces.

Since the first helloworld example does not include any xhtml I thought the file is not needed and so I removed it.

Not surprisingly I received an error when I tried to access the deployed application:

java.lang.NullPointerException

org.jboss.as.quickstarts.helloworld.HelloWorldServlet.doGet(Unknown Source)

javax.servlet.http.HttpServlet.service(HttpServlet.java:734)

javax.servlet.http.HttpServlet.service(HttpServlet.java:847)

What I cannot fathom is how not defining XML namespaces which are not used results in a NullPointerException error.

If anybody can shed some light this will help me improve my mental model and perhaps be able to decipher similarly cryptic messages in the future.

[jaikiran]

Welcome to the forums!

The beans.xml is just a "marker" file to trigger certain container managed services. See this Java EE6 tutorial for more details http://docs.oracle.com/javaee/6/tutorial/doc/gjbnz.html

[mperdikeas]

Thanks. Indeed, I just replaced it with an empty file and it works just file. The "marker only" nature of the file would have been clearer though if it was left blank at the quickstart example.