SLF4JBridgeHandler checks if the message of a LogRecord is null. If so, it does not forward this LogRecord to the underlying logging system. This causes records with null messages to be discarded. If null messages are an issue for certain logging systems it would be preferable to replace the message with an empty string instead of discarding. This way if a Throwable is included in the LogRecord it will still be forwarded to the logging system.