@tariq: pls determine when this breakage first occurred

We have tested above scenario in ADS 15.0.16-1,it's working fine.

This scenario is broken in ADS 15.0.16-2

I have tested this and reproduced this but with the results that in version 15 ads returns error message: You must specify a result setting index. (Ex: .setResultSettings 'index=1'). 

In version 16 it starts returning: Statement failed: java.lang.NullPointerException

I traced the code into CmdSetResultSettings.processArgs() line 157

the List listResultSettings is null here and shouldn't be.

In the calling class execute()

resultsList = (List<ResultSettings>) session.getproperty(AFSession.SYSTEM_RESULT_SETTINGS,null); is returning null but this code hasn't been modified since 2007.

  In version 15 the above line returned a list with 0 items.  In 16 this started returning a null object.

I believe that somewhere the property system.result.settings is getting set to null.  The only place this is set is in AFScriptContect where its set to the <resultSettings> object which from the look of things should not be null but in this scenario is not initialized.

In version 17 code, AFScriptContext line 2047, here _resultSettings is currently null and the property is set, then at line 2081 resizeResultSettings is called and checks if _resultSettings is null and if so makes it a 0 length list, but the property has already been set to null, which is later use to check the results size, maybe be a good idea to reset the property here as well.