// Set date axis style
DateAxis axis = (DateAxis) plot.getDomainAxis();
String formatString = "MM-dd HH";
DateTickUnitType dtut = DateTickUnitType.HOUR;
if (jComboGranularity.getSelectedItem().equals("Year")) {
formatString = "yyyy";
dtut = DateTickUnitType.YEAR;
} else if (jComboGranularity.getSelectedItem().equals("Month")) {