Let's put it in this way:
Properties file which contains key/value pairs for labeling and internationalization of your application. We can say Resource bundle file.
EAR file which contains my application jar files, war files, configuration files which is currently deployed on JBoss AS.
For e.g. my application server is up and running and for displaying a text box label (e.g. User Name) in Flex UI, accepts the value from properties file (Resouce Bundle file).
Now I am making changes to the value present in the property file for any corresponding key (e.g. Your Name instead of User Name) and building the ear file and it is getting hot deployed in JBoss AS.
Now according to the changes made in property file, it should be reflected on Flex UI for the particular text box after hot deploy in JBoss AS which is not happening at my end.
I hope you understand the above scenario.
Also the ref code:
private static final ResourceBundle RESOURCE_BUNDLE = ResourceBundle.getBundle(BUNDLE_NAME,
new Locale(MYEnvironment.getValue("MYUtil", "PART_LOCALE"),localeCountry),Thread.currentThread().getContextClassLoader());
Consider "MYEnvironment.getValue()" part my own dynamic implementation.