Hi @Anna_Setiva,
The delegate expression is used to dynamically resolve the Java class name that is used as a delegate class. After all it is an expression that the engine tries to resolve. In your case it tries to access a property called “getStats”. This property is not there so the process fails with the “unknown property” error.
For your use-case it seems that the delegate will be the same every time. In that case try to use the Java Class implementation for your Service Task.
If you want to make it dynamic and decide which delegate to call, pass a variable called “getStats” with the name of the delegation class as value when starting the process instance.
If you want to learn more about delegates, go to our documentation
Best,
Miklas