When the web.xml includes bad configuration, such as:
...
<listener>
<listener-class></listener-class>
</listener>
...

The exception is cryptic (attached), because it ends up passing the bad entry to JBoss Modules, which also does not handle the exception case well. Several areas where this could be improved:

JBoss Modules should validate the input and provide back a descriptive exception stating "Empty class name" rather than causing a StringOutOfBounds exception.

JBoss Web should provide details that the exception occurred while processing web.xml, which is not immediately clear from the exception produced. Ideally, the exception would also include the location in the XML that had issues validating (application, xml file name, and line number of the exception).