On a mailing list, someone asked about running/integrating Servlets, JSPs, Struts, and EJBs in CF. This is one of those topics that was discussed a lot when CFMX came out, but those who didn't switch at the time may have missed out.
I thought I'd share here my answer to his question (pointing out several resources for him to learn more), in the hope that it may help others also who may only now be considering such integration.
Since he was already familiar with running JSPs on CF, but some readers here may not be, I'll start with just a quick point about that, then I'll offer what I replied to him.
CF and Java Integration
It may be important to clarify that technically, it was CF 4.51 that first afforded the option to integrate with Java (including EJBs). Though CF then wasn't built upon Java, you could point to a JVM in the CF Admin and various CF tags and functions afforded some Java integration.
CFMX 6, however, was not only only built upon Java but the Enterprise (and Developer) edition specifically added the ability to run JSPs and servlets directly within CF. More than that, there's some significant integration possible.
In the case of JSPs, you could just drop them into the same code directory with your CFML templates. Servlets take a little more work, as explained in my reply to the gent's email, below. He had been reading a JSP/servlet book and wanted to know how to run the latter, especially, on CF, as well as how to integrate with the Struts framework:
I hope I can help and I think you'll find I have good news.
You mention looking at a book on JSPs and servlets, and you ask how to implement them (and JSPs) in CF. Of course, that book won't help with that--but neither really will the CFML Reference (or a site like CFQuickdocs), if you may have looked that. You need to look at the ColdFusion Developers Guide in the CF docs (http://livedocs.adobe.com/coldfusion/8/htmldocs/Part_4_CF_DevGuide_1.html), or any CF books out there. The CF manual has a chapter specifically on this topic: Integrating J2EE and Java Elements in CFML Applications.
For instance, that chapter clarifies that to run a servlet called HelloWorldServlet, you put the servlet .java or .class file in the [CFserver]/WEB-INF/classes directory and refer to the servlet with the URL /servlet/HelloWorldServlet. It also discusses sharing data between CFML and such JSPs/servlets. You can even use JSP custom tag libraries directly within CFML, and lots more. And yes, the docs show (briefly) how to enable EJBs and call them from CFML.
That said, the coverage in the docs may leave one wanting more, so you may want to consider other resources that discuss it more. There was at least one book focused on that, Reality Macromedia ColdFusion MX: J2EE Integration. There were also lots of talks and articles back in the 2002 timeframe, when this stuff really took off with CFMX (though Java integration was added back in CF 4.51, which added a means in the CF Admin to point to a JVM that CF would work with.)
For instance, I did lots of presentations on CF/Java integration (as did others, of course). If you visit http://carehart.org/presentations/, and search for java, jsp, or servlet filters.
Doing Struts is not discussed in the CF docs, but there was at least one DevCenter article that discussed it specifically: Streamlining Application Development Using Struts in ColdFusion MX.
It's interesting to see these recent questions about things that came out with CF 6--many shops either didn't move from 4/5 right away, or did but didn't take advantage of the new features. Folks in that position will then not have necessarily followed all the resources (books, technotes, blog entries, user group talks) that came out back then.
This is one of the reasons I keep saying that any topic on the CF Meetup is welcomed. Not everyone needs only to learn new stuff, many need to learn what may seem "old" stuff. It's also the reason why I keep pointing to articles and talks I did in the way past. :-)
Though he didn't ask about it, of course also since CF 6 you 've been able to deploy CFML as a J2EE (or Java EE) web application/WAR or enterprise application EAR. That feature has improved from 6, to 6.1, to 7 (and of course is still possible in 8).
Certainly, if you're a shop that has any Java folks--and especially if there's some strong desire to lean that way, and CF is still seen mistakenly as a proprietary island--it's important to be able to convey to them that your CFML app can be deployed as a pure J2EE web app (WAR/EAR), which is a form they'd expect.
I think all this would be a topic worth my packing together for an upcoming CF meetup session. Until then, again, anyone interested in the topics can see the resources mentioned above that I and others have written.