I have to call to a REST service in the IS from a user task in MWS.
To do so I have to write a Java method in the bindings>services of the task, but apart from that I don’t know what else I’m supposed to do, nor how to try this.
Anybody has done something similar or has any examples?
Why you need to write a Java service you can just create the REST service and request all the user details which are required then call the SearchTask or SearchTaskIndexed any one of the them can be used based on your requriement and you will get the user Task details.
If my understanding is correct ,your userTask will be used from BPM process step. If so , once you deploy (build/upload) your code you can find two service generated in BPM package with name as taskName_InputMapService & taskName_OutputMapService. This two service will get invoked when task is assigned from BPM flow and when task is completed. So, you can put your custom logic in this two step.