JCROM is an acronym that stands for Java Content Repository Object Mapper. It is a simple and lightweight annotation-based framework for mapping Plain Old Java Objects (POJOs) to/from nodes in a Java Content Repository (JCR). This is commonly called Object Content Mapping.
JCR specifies an API for application developers (and application frameworks) to use for interaction with modern content repositories that provide content services such as searching, versioning, transactions, etc.
There are object mapping frameworks for JDBC, like Hibernate and the Enterprise JavaBeans spec. There are also solutions for mapping to/from XML. The vision of JCROM is to provide the same for JCR.