Label in xaxis overlap with each other and are not visible clearly.
yaxis is solved nicely by this code
final NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
rangeAxis.setAutoRangeIncludesZero(true);
I think xaxis values are changed from CategoryAxis but couldn't find the right function that will bring the change.
Thanks