code: public String getUploadFileUrl(String path) {
          final StringBuilder sb = new StringBuilder(GWT.getModuleBaseURL() + UPLOAD_SERVLET_URL);
          sb.append("?").append("path").append("=").append(URL.encode(path));
          return sb.toString();
      }
docs: <p>Returns the upload URL for a given file provided by a servlet method.</p>
  @param path The path of the file.