Hi, Juha-
We run a custom servlet in production that interfaces with OnDemand via the ODWEK java API. We host WebSphere on Windows boxes. I don't know how familiar you are with WebSphere or servlets in general, but installing the prerequisites for working with ODWEK using servlets should take you less than a day--its not "big work."
Let me try and give some detail about what you need to do. You're going to need:
1) WebSphere or another Java application server
2) The ODWEK java API (JAR files)
3) A servlet with which to test, either the "out-of-box" one that comes with ODWEK or a custom one written by you.
4) Since it sounds like you want to write a custom servlet, you'll want a development environment that can package your custom code for deployment to the application server.
As far as (1) installing WebSphere goes, it's a pretty simple process for a plain-vanilla setup. Accept most of the defaults, and elect a local, one-instance installation, its less than an hour.
For (2) the ODWEK Java API, all you have to do is install ODWEK. As you already know, it takes just a few minutes to install.
Now for the time-consuming details:
You'll need to reference ODWEK Java libaries in the classpath of your installed servlet's application context on the application server. On Windows, by default you'll find the high-level library in C:\Program Files\IBM\OnDemand Web Enablement Kit\api\ODApi.jar. You will also need to reference C:\Program Files\IBM\OnDemand Web Enablement Kit\servlets\ArsSVTInterface.class by including it's directory in the classpath. Since ArsSVTInterface.class uses JNI to call native libraries (DLLs in Windows), you need the libraries referenced in the JVM library path. In windows, you can simply copy all the DLL files in C:\Program Files\IBM\OnDemand Web Enablement Kit to your [windows system root]\system32 directory. This is because the library path on Windows includes that directory by default. On UNIX flavors, you'll want to set the JVM library path explicitly to include the location of the native libraries.
(3)
The ODWEK installation comes with a servlet (the so-called "out-of-box" servlet) that's ready-to-go and duplicates the behavior of the CGI interface. The Servlet libraries are installed by default to C:\Program Files\IBM\OnDemand Web Enablement Kit\servlets\ArsWWWServlet.jar. This is the library that you would "deploy" in order to use the out-of-box servlet.
Working with application servers such as WebSphere is famously complicated. If you're not familiar with WebSphere (or at least familiar with Java application servers and servlets in general), packaging and deploying a custom servlet could be non-trivial for you. I've been coding Java for 8+ years, and working with application servers off-and-on for maybe 3 years. I was new to WebSphere, and it took me a couple of days to figure out an appropriate deployment for our custom code.
For the IDE (4), although IBM would probably suggest using IBM's Rational Application Developer (which used to be called WebSphere Studio Application Developer) to develop and package your servlet for deployment, I've been using an open-source environment called Lomboz. Both environments are based on Eclipse, so if you know Eclipse you'll be comfortable.
RAD is at
http://www-306.ibm.com/software/awdtools/developer/application/Lomboz is at
http://forge.objectweb.org/projects/lombozHope this helps,
Elliott