Object mapper
Kundera solves the classical Object-database impedance mismatch problem for NoSQL. Therefore, at a very basic level and for the sake of simplicity, it could be called as Object Mapper for NoSQL.
Kundera is written in Java. It maps premitive data types, wrapper objects and other JPA supported "entity fields" to their counterparts in NoSQL "tables". (Table is a loosely defined term here which would mean different structures in different NoSQL datastores.
Here is a compilation of data types supported in Kundera: