How to use formula for calculated DateTime field using Jira misc plugins?

[Seema]

I would like to calculate datetime when ticket was open and went to resolved/close status.

I am working with Jira misc plugin to get that value. However I get some error message like this "CalculatedDateField: formula does did return a Date object: 728" I got that couple times and after that it shows me different error.

Here is the formula I am using -

<!--@@Formula:issue.get("resolutiondate")==null?null:(issue.get("resolutiondate").getTime() - issue.get("created").getTime())-->

Thanks!

[Marc Jason Mutuc]

Tried the same. Got the same error.