POJava Persistence is a small library of tools used in the persistence and retrieval of data to and from storage, such as to a database or XML document. It contains an ORM (Object Relational Mapping) tool that supports use of existing beans and POJO's rather than requiring POJO's to be instrumented to support a tool.
Xcelite is an ORM like Java library which allows you to easily serialize and deserialize Java beans to/from Excel spreadsheets
MapperDao is an ORM library for the scala language. https://code.google.com/p/mapperdao/
A Utility for making an ORM managed object graph safe for sending to a client by pruning out database proxies circular references and other problematic items
Apache Cayenne is a powerful, full-featured, and open source Java framework, plus developer tools, that provides Object Relational Mapping (ORM) and remoting services for persistence. The software is licensed under the Apache License.