Jetty changed it's packaging in version 7 when it moved to the Eclipse runtimes project. Therefore, the following required class check only works in earlier versions of Jetty.

private static final String JETTY_REQUIRED_CLASS_NAME = "org.mortbay.jetty.servlet.ServletHandler";

boolean jetty = true;
try
{
Reflections.classForName(JETTY_REQUIRED_CLASS_NAME);
}
catch (IllegalArgumentException e)
{
jetty = false;
}

A second check should be performed for the class org.eclipse.jetty.servlet.ServletHandler.

But then we have the issue that the WeldServletHandler extends a class only in Jetty 6. So we'll likely need a special classifier for weld-servlet that runs on jetty 7 and above.