When and why would I need a jboss-deployment-structure.xml for a Spring application?

Question

I am trying to understand how to use JBoss EAP6 with Spring applications. I have a sample OpenShift application and it contains a jboss-deployment-structure.xml file.

I found some documentation about this file, but I am not clear why and when one should use those files with Spring applications. The content is the following:

<jboss-deployment-structure xmlns="urn:jboss:deployment-structure:1.0">
   <deployment>
       <dependencies>
            <module name="com.h2database.h2"/>
            <module name="org.codehaus.jackson.jackson-core-asl"/>
            <module name="org.codehaus.jackson.jackson-mapper-asl"/>
            <module name="org.slf4j"/>
       </dependencies>
   </deployment>
</jboss-deployment-structure>

Why does one need to declare dependencies to modules? And what are modules in the JBoss paradigm? Is it possible to live without this xml file?

Answer 1

As long as you don't have any classloading problems with your application you don't need the jboss-deployment-structure.xml file. But once you have trouble of such kind the dependency management in jboss-deployment-structure.xml would be your friend.

This article explains very good what modules are.

I think in short you can say that everything that is deployed as WAR, JAR or EAR is a module. These modules are referred to as dynamic modules. Beside them there are static modules in $JBOSS_HOME/modules. The only difference is how they are packaged.