In this article I show an example of creating a bar chart with a fixed colour. This was missing from the groovychart example set, and will get included into the next build. If you are unfamiliar with groovy chart then here is an introduction to Groovychart We simply tell the plot’s renderer to use the StandardBarPainter. This turns off the gradient paint that is used by default. Also this example shows one way of using multiple colours in the bars, its probably not the only way and as recommended elsewhere, I suggest the JFreeChart book for anyone intending serious usage of the library.
Groovychart is a library hosted on Java.net that wraps the functionality available in JFreeChart for use as a groovy builder. Currently it is available in snapshot form but hopefully time permitting, a full build will follow soon. I really like groovy as a scripting language, it's great for writing simple UI's for displaying graphical data from many sources including XML and the database. This article helps you set up and get started with groovychart.