At the moment I have this code (and I don't like it): private RenderedImage

private RenderedImage getChartImage (GanttChartModel model, String title,
                                     Integer width, Integer height,
                                     String xAxisLabel, String yAxisLabel,
                                     Boolean showLegend) {
    if (title == null) {
        title = "";
    }
    if (xAxisLabel == null) {
        xAxisLabel = "";
    }
    if (yAxisLabel == null) {
        yAxisLabel = "";
    }
    if (showLegend == null) {
        showLegend = true;
    }
    if (width == null) {
        width = DEFAULT_WIDTH;
    }
    if (height == null) {
        height = DEFAULT_HEIGHT;
    }
    ...
}

How can I improve it?

I have some thoughts about introducing an object which will contain all these parameters as fields and then, maybe, it'll be possible to apply builder pattern. But still don't have clear vision how to implement that and I'm not sure that it's worth to be done. Any other ideas?