Wikipedia
JasperReports
JasperReports is an open source Java reporting tool that can write to a variety of targets, such as: screen, a printer, into PDF, HTML, Microsoft Excel, RTF, ODT, Comma-separated values or XML files.
It can be used in Java-enabled applications, including Java EE or web applications, to generate dynamic content. It reads its instructions from an XML or .jasper file.
JasperReports is part of the Lisog open source stack initiative.