Show notification on a different session

General
1

Hi,

I have a use case when user 1 is doing some actions the user 2 in a different session gets the notification.

On the first user’s action one event is triggered, on listening this event I am using Dialog to show the notification.

But on dialog.open() getting the error “java.lang.IllegalStateException: UI instance is not available. It means that you are calling this method out of a normal workflow where it’s always implicitly set. That may happen if you call the method from the custom thread without ‘UI::access’ or from tests without proper initialization.”

Could someone please help?

Regards,
Amal Suresh

type or paste code here
2

Can you please show your code? Most likely you are opening the dialog from a background thread without using UI.access, as stated in the error message.

For more info about asynchronous updates look at Server Push | Advanced Topics | Flow | Vaadin Docs

3

Here’s a cookbook recipe for something very similar: How do I show a notification to active users - Vaadin Cookbook

As Marco said, the likely problem is that you’re not updating the UI through ui.access