Message bundle is the base name of a resource bundle representing the message resources of the Web application. See the java.util.ResourceBundle class at http://java.sun.com for information on the syntax of resource bundle names.
To add message bundle:
Select faces-config.xml in the Project Explorer of the J2EE perspective.
The JSF Application Configuration editor opens.
Select the Other tab of the editor.
The Other page appears.
Expand the Message Bundle section.
Click Add.
The Select Message Bundle dialog box opens.
Select the message bundle that you want to use and click OK.
The message bundle you selected displays in the list.