JFreeChart is a class library, written in Java, for generating charts. Utilising the Java2D APIs, it currently supports bar charts, pie charts, line charts, XY-plots and time series plots.
charts4j is a free, lightweight charts and graphs Java API. It enables developers to programmatically create the charts available in the Google Chart API through a straightforward and intuitive Java API.
jCharts is a 100% Java based charting utility that outputs a variety of charts. This package has been designed from the ground up by volunteers for displaying charts via Servlets, JSP's, and Swing apps. First release was in December 2000.
jtstand-chart is a swing chart library derived from jfreechart