I need a commercial-friendly (Apache Licence, LGPL, Mozilla Public License etc) R-tree implementation in Java, in order to substitute the geonames Web Service for timezones, as suggested in the question "Determine timezone from latitude/longitude without using web services like Geonames.org". I have found some around, but I was wondering if someone has evaluated or used them in practice.
https://github.com/rweeks/util/blob/master/src/com/newbrightidea/util/RTree.java - LGPL implementation of R-Tree by Russ Weeks. It looks very simple and clear and not dependent on external libraries.
http://www.mischiefblog.com/?p=171 http://www.mischiefbox.com/blog/uploads/rtree.jar LGPL implementation of R-Tree by Chris Jones. Another simple and clear solution.
http://www.khelekore.org/prtree/ CPL 1.0 implementation of Priority R-Tree by Robert Olofsson
http://jsi.sourceforge.net/ LGPL - project aims to maintain a high performance Java version of the RTree spatial indexing algorithm.