A CachedRowSet object is special in that it can operate without being connected to its data source, that is, it is a disconnected RowSet object. It gets its name from the fact that it stores (caches) its data in memory so that it can operate on its own data rather than on the data stored in a database.
Is Ehcache a NoSQL store? No, I would not characterise it as that, but I have seen it used for some NoSQL use cases. In these situations it compared very well — with higher performance and more flexible consistency than the well-known NoSQL stores. Let me explain.
Michael Martin, Jörg Unbehauen, and Sören Auer. Proceedings of 7th Extended Semantic Web Conference (ESWC 2010), 30 May -- 3 June 2010, Heraklion, Crete, Greece, volume 6089 of Lecture Notes in Computer Science, page 304-318. Berlin / Heidelberg, Springer, (2010)