Just to be clear, I don't want to endup with a fat class like : | public class AorBorC { | | // Types | public static final int A_TYPE = 0; | public static final int B_TYPE = 1; | public static final int C_TYPE = 2; | | // Type | private int type; | | // Common attributes | private String commonAtt1; | private String commonAtt2; | | // Only apply to A | private int specificAttForA; | | // Only apply to B or C | private int specificAttForBorC; | | // Only apply to C | private int specificAttForC; | } | The example of hierarchy of class I am talking about is similar to org.jboss.portal.portlet.invocation.response.PortletInvocationResponse View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4061791#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...