Created attachment 1076537 [details]
Log from smoke tests showing the NPE caused when the script task is executed in a process

Description of problem:

The "data services" in BPMS/kie-wb, which are located in the jbpm-kie-services module, piggy-back on the code used to actually used to build the process instance. 

However, there seems to be a race condition in which the data services/jbpm-kie-services builder code (instead of the normal/jbpm-bpmn2 builder code) is used to build a process instance. 

When that happens, the process instance is not completely built because the data services builder logic only collects information, but does not build the process instance. 

This results in, among other things, an NullPointerException when a script task is executed, because the script task "Action" has not been completely built. 

Version-Release number of selected component (if applicable):

As of community 6.3.x. 


How reproducible:

This is not always reproducible because the problem is caused by a race condition [https://en.wikipedia.org/wiki/Race_condition]. 


Steps to Reproduce:
1. Repeatedly start a process containing a script task in BPMS/kie-wb. 

The race condition seems to be most likely to happen immediately after a deployment is deployed. 

Actual results:

An NPE is thrown (see attached log from our smoke tests). 

Expected results:

The process completes without error.