iReport is a very powerful, graphical reporting tool created by SourceForge. It is an open source software that is also based on Java. iReport works very well with enJin®!
The files created by iReport use enJin®’s database connection to create a pdf output that can then be viewed with enJin®’s internal pdf-viewer.
For more information on iReport check out http://www.jasperforge.org/