1.- webview is not a full fledged browser, so do not thrust it
2.- to create an executable jar, compile in release mode and go to your porject folder (where the .b4j program is) there will be a objects folder, insde that folder is your jar
3.- UI apps (the ones that use the webview for example) do not run in raspberry. you will have to do acrobatics for it and it is not worth it.