For Jetty 7 a lot of re-factoring has been done on the Continuations API. I recently took a look at the changes and modified DWR’s code to reflect the latest API. If you are using the latest version of DWR 3.x (currently unreleased) and you are still using a Jetty version < 7.x you will need to follow these directions to get Continuations working. First you will need to download the Jetty continuation 7 jar and place it in WEB-INF/lib. You can read more about why this works here.

Next you will need to add the JettyContinuationFilter to your web.xml:

<filter>
    <filter-name>JettyContinuationFilter</filter-name>
    <filter-class>org.eclipse.jetty.continuation.ContinuationFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>JettyContinuationFilter</filter-name>
    <url-pattern>/dwr/*</url-pattern>
</filter-mapping>

You should now be up and running.