Ace editor using Servlet 3.0

Hi all!
I’ll be direct. I’m using the Ace Editor vaadin wrapper. In their github page they say that in order to use custom acemodes you have to host in your server. Ok. Then they give an example and point me to modify my web.xml file to add a mapping

<servlet-mapping> <servlet-name>default</servlet-name> <url-pattern>/static/*</url-pattern> </servlet-mapping

I’m using the servlet 3.0 config without a web.xml. I can’t get ace editor to find its files in webcontent =(
What should I do? I must drop the 3.0 configuration and use a web.xml?