Log4J Features  Basic features of any logging library are: 1.
Control over which logging statements are enabled or disabled -
the Logger, the central class in the log4j package. 2. Manage
output destinations - Appenders, there are appenders for files,
the console, Unix Syslog, NT Event Log, remote servers, SMTP
e-mail, etc. 3.Manage output format- Layouts, the most popular
layouts are the PatternLayout and HTMLLayout.  As mentioned
above Log4j has three main components: loggers, appenders and
layouts. 1. public class Logger- Logger is responsible for
handling the majority of log operations. 2. public interface
Appender - Appender is responsible for controlling the output of
log operations. 3. public abstract class Layout-Layout is
responsible for formatting the output for Appender.  These three
types of components work together to enable developers to log
messages according to message type and level, and to control at
runtime how these messages are formatted and where they are
reported.   Log4j Features Log4j