In my previous emails, usage of lowercase message (the formatted string) and uppercase Message (the Message object) may be a bit confusing. And, if a Message object is to be constructed, my thought is that it should encapsulate all data, including the Throwable. This would help out when splitting off a trailing Throwable from the raw argument list when formatting a message. So, a better name for the Message object may be Entry. Entry would fully encapsulate all non NDC/MDC data including the lowercase raw and formatted message, parameters, a Throwable, and extra entry specific data. Entry would be responsible for formatting. public interface Entry { String getFormattedMessage(); String getMessagePattern(); Object[] getParameters(); // without trailing throwable Throwable getThrowable(); Map<String, Object> getSupplementalData(); } John