How do i replace activityInstance.getActivityDefinitionUUID() in version 7.x?

String url = "https://xyz.com/bonita/console/homepage?locale=default&theme="+processDefinition.getUUID().toString()+"#form="+activityInstance.getActivityDefinitionUUID().toString()+entry+"&task="+activityInstance.getUUID().toString()+"&mode=app";
i replaced processdefinition and activityInstance with the provided variables.
I am using this link to redirect the user to a human task from his mail box.
How do i replace activityInstance.getActivityDefinitionUUID()?

Regards
A.