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I'm new to Spring and Vaadin and though I'm trying to go through tutorial for views navigation.

My project is very, very simple and just for hobby and learning purpose. But if it works for me I'll maybe try to use Vaadin in my job too. I use no configuration class nor any XML - only Java annotations. I'd like to enable @Push eventually to update views periodically with data fetched from DB.

Could anyone help me to fix the example code? I'm getting following warnings and I'm not sure what can be done with it and what will be the result of ignoring them.

First one is:

onClassPostProcessor : Cannot enhance @Configuration bean definition 'com.vaadin.spring.VaadinConfiguration' since its singleton instance has been created too early.
The typical cause is a non-static @Bean method with a BeanDefinitionRegistryPostProcessor return type:
Consider declaring such methods as 'static'.

And another one is only when I add compile("com.vaadin:vaadin-push") dependancy:

o.a.util.IOUtils     : More than one Servlet Mapping defined. 
WebSocket may not work org.apache.catalina.core.ApplicationServletRegistration

Detailed information and all the necessary files with code required to reproduce the issue are here: stack overflow question.

I guess that everything is done as in the tutorial (which my code is only a small subset of) or am I missing something?

If there is nothing to worry about with these warnings then maybe it's worth mentioning that in the tutorial itself.