<p>I'm using the build-helper-maven-plugin to add it to my build, but I'd
like to see the XREF source for this extra source directory as well.</p>

<p>FYI:</p>

<p><a href="http://maven.apache.org/plugins/maven-jxr-plugin/index.html" rel="nofollow noreferrer">maven-jxr-plugin</a> - The JXR plugin produces a cross-reference of the project's sources. The generated reports make it easier for the user to reference or find specific lines of code. It is also handy when used with the PMD plugin for referencing errors found in the code.</p>

<p><a href="http://mojo.codehaus.org/build-helper-maven-plugin/index.html" rel="nofollow noreferrer">build-helper-maven-plugin</a> - This plugin contains various small independent goals to assist with Maven build lifecycle.</p>

You have to expose your DAO's or beans by means of http. Typically you create a layer above the DAO layer to expose your services through HTTP, which are available to any AJAX framework such as jQuery. What jQuery and other frameworks ends up doing is using a special asynchronous request called XMLHttpRequest and then parse the server response (can be anything, pure HTML, JSON, XML, etc) and process it.
Here's a link I found that shows Spring & DWR with AJAX:
Bram Smeets Blog
.