Migration of MAPPER data reports is informed by configuration metadata based on the Spring framework. More specifically, MJ relies on Spring to configure and instantiate beans of various types, including column definition beans, data entity handler beans, inline data handler beans, and enumeration mapping beans. Each of these beans is explained as the related topic arises in the documentation.

Beans are simply Java classes that define setter and getter methods to set and access properties of the bean. Initializion of a bean may also occur via the constructor of the Java class. Spring's XML configuration readily supports setter and constructor "injection".

A key aspect of Spring is that one bean may reference another bean. Stated another way, a bean may have a dependency on other beans. The "other" beans are known as collaborating beans. For example, in MJ, database columns are defined by column definition beans; the column definition beans are then referenced as collaborating beans by a data entity handler bean. Spring uses dependency injection to resolve this kind of relationship between beans.

See core Spring technologies for further information.