code: protected boolean initURL(String data) {
        if (getUrl() == null) {
           if (log.isLoggable(Level.FINE)) {
              log.fine(String.format("url parameter is null, trying to construct one from %s", data));
           }
           try {
              setUrl(BindingHelper.URL_PARSER.convert(data));
              return true;
           } catch (VectorPrintRuntimeException ex) {
              if (log.isLoggable(Level.WARNING)) {
                 log.warning(String.format("no url: %s", data));
              }
           }
        }
        return false;
     }
docs: when {@link #getUrl() } is null try to convert the data argument to a URL and call {@link #setUrl(java.net.URL) }.
  
  @param data the data from {@link BaseStyler#style(java.lang.Object, java.lang.Object) } or from {@link #getData()
  }
  @return true when a url was successfully constructed from the argument