code: public /*@Nullable*/String createShareableUrl(String path)
          throws DbxException
      {
          DbxPathV1.checkArg("path", path);
  
          String apiPath = "1/shares/auto" + path;
          String[] params = {"short_url", "false"};
  
          return doPost(host.getApi(), apiPath, params, null, new DbxRequestUtil.ResponseHandler</*@Nullable*/String>() {
              @Override
              public /*@Nullable*/String handle(HttpRequestor.Response response)
                  throws DbxException
              {
                  if (response.getStatusCode() == 404) return null;
                  if (response.getStatusCode() != 200) throw DbxRequestUtil.unexpectedStatus(response);
                  DbxUrlWithExpiration uwe = DbxRequestUtil.readJsonFromResponse(DbxUrlWithExpiration.Reader, response);
                  return uwe.url;
              }
          });
      }
docs: Creates and returns a publicly-shareable URL to a file or folder's "preview page".
  This URL can be used without authentication.  The preview page may contain a thumbnail or
  some other preview of the file, along with a link to download the actual filel.
  
  @param path
  The Dropbox path to a file or folder.
  
  @return
  If there is no file or folder at that path, return {@code null}.  Otherwise return
  a shareable URL.