Absolutely you can create external tasks, url tasks, etc. using Java / JSPs if you wish to do so. More than likely you'll be utilizing CSSDK APIs...
Thanks for your reply, can you provide any reference where I can find the sample usage of similar implementation. I had tried to find in manuals but no pointers to do so is given in manuals.thanks
I second Dave's post. I am not sure if you have read the WFM guide -- there are specific chapters on topics like "using datasource framework", "using custom code", etc. that clearly talks about using Java code. I am sure there are other chapters in that same guide that provide relevant information. I'd recommend reading this guide thoroughly and then post specific questions.
I am using WFT so is it necessary to use only WFM for implementing Java enabled tasks??