code: public static void changeMarkSize( Rule rule, int newSize ) {
          PointSymbolizer pointSymbolizer = StyleUtilities.pointSymbolizerFromRule(rule);
          Graphic graphic = SLD.graphic(pointSymbolizer);
          graphic.setSize(ff.literal(newSize));
          // Mark oldMark = SLDs.mark(pointSymbolizer);
          // oldMark.setSize(ff.literal(newSize));
          // Graphic graphic = SLDs.graphic(pointSymbolizer);
      }
docs: Changes the size of a mark inside a rule.
  
  @param rule the {@link Rule}.
  @param newSize the new size.