If we got two properties file in the struts application. and you configure in struts-config.xml. Then if you are using these properties file in jsp page . then how the jsp page will know from which properties file it had take the label.
When you set up two Message Resource bundles in struts-config.xml, you must specify a key attribute with at least one of them. The one without the key attribute will be considered the default bundle. When you want to use the non-default bundle, you must specify a bundle attribute in the tag.