JHeatChart is a one class Java API for generating heat map charts that was created because very few charting APIs seem to contain the facility to create heat maps. It is not a full featured charting API and cannot be used to other charts. The generated charts are created as Java Image objects, which can be incorporated into a GUI or saved to a file.
Aspose.Cells for JasperReports allows you to exports reports from JasperReports and JasperServer in Microsoft Excel spreadsheet (XLS) format. It is provided as a single JAR file that can easily be deployed on machines running JasperReports or JasperServer. It exports Excel charts as editable charts rather than static pictures so that they can be edited manually in MS Excel.