A script task provides an ability to set a Groovy script that is executed when a process execution arrives at the task.
All process variables are accessible within the script. In the script below, the
startAmount variable is a process variable:
result = startAmount + 10
The result of the script will be stored in the process variable defined in the Result variable field:
Also, it is possible to set process variables in a script by calling
execution.setVariable("variableName", variableValue). The variable will be stored automatically.
For more details about script tasks, see Flowable documentation.