What I really want to do, as a first step, is to insert Java code into a Service task and run it in the JBPM Console. Using work item definitions is secondary.
For example, executing Java code in a Script task is easy. I simple put the code in the script attribute, save the process and run the process containing the Script task in the JBPM Console.
Service tasks are less obvious. Setting aside the issue of work items, how do you insert Java code into a Service task in the way you can with a Script task? I'm just looking first to get a simple process containing one service task to run in the JBPM Console.