The JTS Topology Suite is an API of 2D spatial predicates and functions. It has
the following design goals:

    * JTS conforms to the Simple Features Specification for SQL published by the
	Open GIS Consortium
    * JTS provides a complete, consistent, robust implementation of fundamental
	2D spatial algorithms
    * JTS is fast enough for production use
    * JTS is written in 100% pure Java(TM)
    * JTS is open source (under the LGPL license)

WWW: http://www.vividsolutions.com/Jts/JTSHome.htm