Java ORMs for MongoDB

• MJORM (mongo-java-orm) - A MongoDB Java ORM

This project aims to provide a robust query api and ORM for MongoDB and the Java programming language
https://code.google.com/p/mongo-java-orm/

• Spring Data - MongoDB

Spring Data for MongoDB is part of the umbrella Spring Data project which aims to provide a familiar and consistent Spring-based programming model for for new datastores while retaining store-specific features and capabilities
http://www.springsource.org/spring-data/mongodb

• Morphia

Morphia is a lightweight type-safe library for mapping Java objects to/from MongoDB:
https://code.google.com/p/morphia/

• jongo

http://jongo.org/

• Hibernate OGM

Hibernate OGM is an attempt to store data in a NoSQL data grid using the Hibernate ORM engine rather than rewriting a JPA engine from scratch.
https://github.com/hibernate/hibernate-ogm