22.4. CMP Fields

CMP fields are declared on the bean class as abstract getter and setter methods that follow the JavaBean property accessor conventions. Our gangster bean, for example, has a getName() and a setName() method for accessing the name CMP field. In this section we will look at how the configure these declared CMP fields and control the persistence and behavior.

22.4.1. CMP Field Declaration

The declaration of a CMP field starts in the ejb-jar.xml file. On the gangster bean, for example, the gangsterId, name, nickName and badness would be declared in the ejb-jar.xml file as follows: 
<ejb-jar>
  <enterprise-beans>
    <entity>
        <ejb-name>GangsterEJB</ejb-name>
        <cmp-field><field-name>gangsterId</field-name></cmp-field>
        <cmp-field><field-name>name</field-name></cmp-field>
        <cmp-field><field-name>nickName</field-name></cmp-field>
        <cmp-field><field-name>badness</field-name></cmp-field>
    </entity>
  </enterprise-beans>
            </ejb-jar>
Note that the J2EE deployment descriptor doesn't declare any object-relational mapping details or other configuration. It is nothing more than a simple declaration of the CMP fields.