App with multiple WAR files

Question

We have a customer self-service web site, freshly re-implemented using facelets in a WAR file. It works fine. We are just now starting to re-implement a second significant component from the previous generation. This component is pretty complicated, so we would like to maintain and deploy it individually in its own WAR. However, we would like this component to blend smoothly in the primary application. Ideally, the main app would create a borderless window in which this component would live, but everything inside that window would be controlled by the second WAR file. Both WAR files run on the same web server, and if it helps, can run in the same session.
In previous times, we might have done this with an iframe to contain the second application. But I'm well aware of the downsides of iframes and that they are strongly discouraged in new apps, What is the current recommended approach for blending multiple WAR files into what appears to be a single application to the end user? Portlets? Can I easily make a simple facelets application (our primary app) into a portlet container without making it into a full scale portal? All the portlet examples I find show the portlet in a window that the user can minimize or maximize. Can our primary app hide those window controls so that the contents of the second WAR appear to be part of the primary application?
Thanks for any and all suggestions. I've spent a couple hours searching for "multiple war files" and "external war" and didn't find any useful leads.

Answer 1

But I'm well aware of the downsides of iframes and that they are strongly discouraged in new apps,If it solves your problem, what would be bad about it? I wouldn't use iframes to merge applications from different hosts, but when the sub-applications are part of one larger application that you have under your own control, then why not?
It is fine to follow current trends, but only if it is intelligent to do so.