This is an easy error to get when you aren’t paying attention. What happened is you included com.google.gwt.http.client.URL on the server-side to try and decode an encoded URL. What you want to use is java.net.URLDecoder. Also related, the string is by default encoded UTF-8, so decode like this: String s = URLDecoder.decode(string, “UTF-8”);
Maybe someone else will find this instead of having to search for it.