WooF7 is a free JDBC driver for accessing FileMaker Server from Java applications. Compared to the standard JDBC driver that ships with FileMaker, it is smaller, more standards-compliant, and open source.
In addition to the JDBC driver, WooF7 is packaged with a compatibility layer for using FileMaker with WebObjects.
WooF7 is a GPL (GNU Public License) open source application. The source code can be downloaded at http://code.google.com/p/prosc-woof/