log4j와 java util logging의 차이

http://onjava.com/pub/a/onjava/2004/09/29/smtp-logging.html

	log4j	java.util.logging
Manager class	org.apache.log4j.LogManager	java.util.logging.LogManager
Logger objects	org.apache.log4j.Logger	java.util.logging.Logger
Named loggers	Supported	Supported
Logging levels	Levels are declared in the org.apache.log4j.Level class. log4j has five pre-defined levels: FATAL ERROR WARN INFO DEBUG	Levels are declared in the java.util.logging.Level class. There are seven pre-defined levels: SEVERE WARNING INFO CONFIG FINE FINER FINEST
Log event object	org.apache.log4j.spi.LoggingEvent	java.util.logging.LogRecord
Output destinations	Appender classes. These classes implement the org.apache.log4j.Appender interface.	Handler classes. These classes extend java.util.logging.Handler.
Output message filtering	Filter classes. These classes extend org.apache.log4j.spi.Filter.	Filter classes. These classes must implement the java.util.logging.Filter interface.
Output message formatting	Layout classes extend org.apache.log4j.Layout.	Formatter classes extend java.util.logging.Formatter.
Programmatic configuration	Supported	Supported
Property file configuration	Supported	Supported
XML configuration	Supported. The XML configuration file must comply with log4j.dtd.	Not supported
Email notification	SMTPAppender class	SMTPHandler class (third-party extension

추후 다양한 Appender를 만들기 위해서 정확히 이해할 필요 있음..