Process instance variables are associated with an execution. So you need the executionId. Since you supplied the variables right at the start of the process they belong to the parent execution which id equals the processInstanceId (AFAIK). So you can retrieve the variables programmatically by using the processInstanceId.
Within a process definition you can use expressions to access process instance variables. For this refer to the user guide.
You can always add additional variables to the process. See the set-method for process instance variables for this.
Thanks for the reply.. My mistake was to check at the process instance level while I am suppose to check at the execution level and task service level.
I got it working. Thanks for your detailed explanation.
hi , can you please post the code to get the process variables during the time of execution?