public MessagesImpl(Locale locale,
    ResourceBundle bundle) 
{
        super(locale);
        // Our best (threadsafe) chance to determine all the available keys.
        Enumeration< String > e = bundle.getKeys();
        while (e.hasMoreElements())
        {
            String key = e.nextElement();
            String value = bundle.getString(key);
            properties.put(key, value);
        }
}

 public static Messages forClass(Class forClass) 
{
        String className = forClass.getName();
        String stringsClassName = className.replaceAll("Messages$", "Strings");
        Locale locale = Locale.getDefault();
        ResourceBundle bundle = ResourceBundle.getBundle(stringsClassName, locale, forClass.getClassLoader());
        return new MessagesImpl(locale, bundle);
}

Finds the messages for a given Messages utility class. Strings the trailing "Messages" and replaces it with "Strings" to form the base path. Loads the bundle using the default locale, and the class' class loader.

 protected String valueForKey(String key) 
{
        return properties.get(key);
}