title: HeatMaps with JFreeChart
body: <p>I have a dataset of points (x,y) and I would like to create an heatmap of this dataset. More specifically, I would like an image in which I have lighter colors in the areas where I have a bigger concentration of points and darker where there are less points.
  I am using JFreeChart libraries and I found some classes for example DefaultHeatMapDataset but I am not sure how to use them in the proper way.</p>
  
  <p>Does anybody has a clue on how to do it? </p>
  
  <p>Thanks in advance!
  Giovanni </p>