VaadinBootstrap.js loading issue

I’m new to Vaadin. I am trying to run the VAADIN project from the tutorial and when I execute it, I get a message "

Failed to load the bootstrap javascript: ./VAADIN/vaadinBootstrap.js?v=7.5.10


Please advice.

Thank you

have you compiled widgetset successfully?

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Hello Aziz, Thanks for the reply. I have added the vaadin maven plugin and did the mvn vaadin:compile and then run it and yet it doesn’t work. Ofcourse, I see the components in the browser however, I also see a banner on the top that says "

(SyntaxError): expected expression, got ‘<’ - Original JSON-text:html>


Any suggestions?

could you verfiy if your servlet mapping is correctly done. Please attach your web.xml.
could you please attach a screen shot of the error as well.
Thanks and cheers,

I do not have a web.xml; Code is the exact copy of

No difference.

I the code the ServletMapping is a annotation in

any ideas?


I had a similar issue, and it was my app-server running with servlet2.0 specifications (servlet annotation not supported).
In my case it was an old web.xml with 2.0 header.
Could also be you appserver is too old ?
(If running in Eclipse, check demo readme :

Wich app-server do you use ? Tomcat 8 should be a good start.


Hello Sebastien, Thanks for the post.

I re-did the code and surprisingly it worked just fine. Perhaps I missed something earlier.