Thanks a lot to Mark who gave me the following insight.
I believe you're problem is related to not understanding the logging PRIORITY or levels. There's a precedence with DEBUG being the lowest and FATAL being the highest. This is the reason that you are not seeing your output - you've told L4J to not output anything with a lower priority than INFO - which DEBUG is. You need to log messages as INFO or alternatively, keep your code the same and revert your priority to DEBUG.
I had never played with setting priorities at Appender level before.