example3/Messages.java

package example3;
import java.util.MissingResourceException;

public class Messages {

    private Messages() {
    }

    public static String getString(String key) {
        try {
            return SystemInfo.RESOURCE_BUNDLE.getString(key);
        } catch (MissingResourceException e) {
            return '!' + key + '!';
        }
    }
    
}