Using Mongo with it's Java driver can be tricky:
Queries have to be written using a criteria like style, results are untyped and have to be manually mapped.
Jongo makes it easy:
Queries can be written as String, results can be unmarshalled as any Java object.
Documentation available at jongo.org
Java docs at https://jongo.ci.cloudbees.com/job/jongo-ci/site/apidocs/index.html