Something to be aware of, and that works really well!
SEXTANTE is a spatial data analysis library written in Java. The main aim of SEXTANTE is to provide a platform for the easy implementation, deployment and usage of rich geoprocessing functionality. It currently contains more than three hundred algorithms for both raster and vector data processing, as well as tabular data analysis tools. SEXTANTE integrates seamlessly with many open source Java GIS (such as gvSIG, uDig or OpenJUMP) and non-GIS tools (such as the 52N WPS server or the spatial ETL Talend).
SEXTANTE is free software and is distributed under a MIT license.
Let me know if any of you has a chance to play with it. FYI, it’s coming to ArcGIS 10 very soon!!!