nz.ac.waikato.cms.moa:moa (maven):  Massive On-line Analysis is an environment for massive data mining. MOA provides a framework for data stream mining and includes tools for evaluation and a collection of machine learning algorithms. Related to the WEKA project, also written in Java, while scaling to more demanding problems. 
Keywords: clustering|data-stream-mining|java|machine-learning|machine-learning-algorithms|moa|streaming-algorithms