title: What is a good (free) library to make a contour plot in Java?
body: <p>What are good libraries to create a Contour plot in Java?
  The class <a href="http://www.jfree.org/jfreechart/api/javadoc/org/jfree/chart/plot/ContourPlot.html" rel="nofollow">ContourPlot</a> in JFreeChart is deprecated, and a reference is made to the XYBlockRenderer class.
  I would like to have some suggestions.</p>