provide implemnentation of WorkItemHandler that allows asynchronous execution utilizing jbpm executor component. It should be enough to provide only the logic that shall be executed - in form of a Command that executor can simply invoke.
All parameters shall be given as contextual data to the command - meaning work item and it's parameters shall be available to the command.
Command implementation should not care about process related things like completing work item to move process instance forward. Instead it should purely contain business logic to be executed and return results.