Forcing Atmosphere AsyncSupport - Atmosphere/atmosphere Wiki

In case your application's contains both Tomcat and Jetty runtime, Atmosphere may fail to detect the proper AsyncSupport class. To fix the issue, just add in your web/application.xml

        <init-param>
            <param-name>org.atmosphere.cpr.asyncSupport</param-name>
            <param-value>org.atmosphere.container.*</param-value>
        </init-param>

available value are listed here For example, enabling Jetty 7/8

        <init-param>
            <param-name>org.atmosphere.cpr.asyncSupport</param-name>
            <param-value>org.atmosphere.container.Jetty7CometSupport</param-value>
        </init-param>