I am using time series. I am trying to : 1. static class CustomizedStandardXYSeriesLabelGenerator extends StandardXYSeriesLabelGenerator { private static final long serialVersionUID = 1L; TimeSeriesCollection xydataset; CustomizedStandardXYSeriesLabelGenerator(TimeSeriesCollection xydataset) { this.xydataset = xydataset; } public String generateItemLabel(int series){ return this.xydataset.getSeries(series).getDescription(); } } 2. //set the customized legend label generator renderer.setLegendItemLabelGenerator(new CustomizedStandardXYSeriesLabelGenerator(xydataset)); where "xydataset" is an object of "TimeSeriesCollection" 3. xydataset.getSeries(2*attackTypes.length).setDescription("Before Filtering"); then ...