Creating a custom email handler for Jira

[aas]

Hi everyone. I try to create a custom email handler for Jira with my UI using this tutorial https://developer.atlassian.com/server/jira/platform/creating-a-custom-mail-handler-for-jira/ .

In step 8 I can't understand which class will handle data from form in editDemoHandlerDetails.vm, is it EditDemoHandlerDetailsWebAction? In form attribute action there are action="EditDemoHandlerDetails.jspa" 

Will be glad for any help.