A formatter is a logging component that determines how log messages are printed before an appender stores or displays them. It can add details such as timestamps and severity levels, allowing application code to provide only the message description. section 4.2.2
Console output with PatternLayout
A Log4j Console appender uses PatternLayout with a pattern containing the date, thread, severity level, logger name, message, and line ending. The resulting output records entries such as an INFO message reporting extracted digits.
