Vaadin “A connector with id xy is already registered”

Question

Somewhere in my Vaadin application, I\'m getting this exception as soon as I connect using a second browser

Caused by: java.lang.RuntimeException: A connector

Answer 1

Here is how I fixed it -

1) look for components you have shared across sessions. For example if you have declared a component as static it will be created once and will be shared.

2) if you are not able to find it and want a work around until you figure out the real problem, put your all addComponent calls in try and in catch add following code -

getUI().getConnectorTracker().markAllConnectorsDirty();
getUI().getConnectorTracker().markAllClientSidesUnititialized();
getPage().reload():

This will clear old connectors and will reload the page properly only when it fails. For me it was failing when I was logged out and logged in back.

Once you find the real problem you can fix it till then inform your customers about the reload.

**** note - only solution is to remove shared components this is just a work around.