After Installing Vaadin plugin and downloading Vaadin jars, and configuring the build path. An error is keeping on occur when building the project, something related to org.jsoup.nodes.Element but I couldn't figure out why.
The type org.jsoup.nodes.Element cannot be resolved. It is indirectly referenced from required .class files
On
I had this problem and I couldn't figure out what was causing it. After trying different ways to solve it, I was suggested to clear the ivy2 cache and resolve again the dependencies by using a different network connection that doesn't involve a proxy. It worked and eventually the jsoup jar was added to the library. Apparently, when downloading the first time the dependencies jars, the jsoup one was blocked by the proxy, and the missing jar in the cache went undetected.
It seems you are missing the jsoup dependency of vaadin. If you have downloaded the vaadin jars manually the dependencies are missing. It is better to use a build tool like maven or gradle, that automatically takes care of downloading dependencies. Vaadin has a couple of other dependencies which you would all need to download separately if you were just using an IDE.
You can generate a maven or gradle project that is ready to run using Spring's Initializer.