log4j version 1.2.16
API Specification

Packages

org.apache.log4j	The main log4j package.
org.apache.log4j.chainsaw	Chainsaw is a GUI log viewer and filter for the log4j package.
org.apache.log4j.config	Package used in getting/setting component properties.
org.apache.log4j.helpers	This package is used internally.
org.apache.log4j.jdbc	The JDBCAppender provides for sending log events to a database.
org.apache.log4j.jmx	This package lets you manage log4j settings using JMX.
org.apache.log4j.lf5
org.apache.log4j.net	Package for remote logging.
org.apache.log4j.nt	Package for NT event logging.
org.apache.log4j.or	ObjectRenders are resposible for rendering messages depending on their class type.
org.apache.log4j.or.jms	This package contains the MessageRenderer which renders objects of type javax.jms.Message.
org.apache.log4j.or.sax	This package contains the AttributesRenderer which renders object of class org.xml.sax.Attributes.
org.apache.log4j.spi	Contains part of the System Programming Interface (SPI) needed to extend log4j.
org.apache.log4j.varia	Contains various appenders, filters and other odds and ends.
org.apache.log4j.xml	XML based components.