RapidMiner (YALE): Java Data Mining

RapidMiner (formerly YALE) is the most comprehensive open-source software for intelligent data analysis, data mining, knowledge discovery, machine learning, predictive analytics, forecasting, and analytics in business intelligence (BI). RapidMiner provides more than 400 data mining operators, a graphical user interface (GUI), an online tutorial with hands-on data mining applications, a comprehensive PDF tutorial, many visualization schemes for data sets and data mining results, many different learning and meta-learning schemes ranging from decision tree and rule learners to neural networks, SVMs, ensemble methods, etc.
RapidMiner is implemented in Java and available under GPL (GNU General Public License) as well as under a developer license (OEM license) for closed-source developers