error when connection mysql with vaadin : I'm trying to make a connection between mysql and vaadin, when implementing the project, the current browser show error as picture [enter image description here][1]


  [1]: https://i.stack.imgur.com/Fe2nl.png

because I do not know how to insert my code, I posted it to google drriver
https://drive.google.com/open?id=1VlcOAiZ1ecYY6SYT6fNBi0IpspVHIJpa