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.
CleanSheets is a spreadsheet application that is both extensible and platform-independent. It features a formula language that closely resembles that of Microsoft Excel, and extensions for aiding end-user programmers in developing correct spreadsheets. The application is written in Java, and relies on ANTLR for generating the formula compiler and the JFC/Swing JTable component for spreadsheet visualization.