Using log4j in Java Program

public static Logger logger_name = Logger.getLogger(classname.class);

PropertyConfigurator.configure(System.getProperty("user.dir") + "\\config\\log4j.properties");

EX:
public static Logger APP_LOGS = Logger.getLogger(DriverScript.class.getName());

log4j.properties:

# Define the root logger with appender file

log = TestOutput/Logs

log4j.rootLogger = INFO, FILE

# log4j.rootLogger = INFO,console, FILE ( To print all logging messages to both the console and a log file)

# Define the file appender(RollingFileAppender OR ConsoleAppender(to print in console))

log4j.appender.FILE=org.apache.log4j.RollingFileAppender
log4j.appender.FILE.File=${log}/SFDCTests.html

# Constrole the maximum log file size

log4j.appender.FILE.maxFileSize=10000KB

# Archive log files (one backup file here)

log4j.appender.FILE.maxBackupIndex=3

# Define the layout for file appender
(HTMLLayout OR PatternLayout)

log4j.appender.FILE.layout=org.apache.log4j.HTMLLayout

log4j.appender.FILE.layout.Title=Logger For SFDC Test Cases

log4j.appender.FILE.layout.LocationInfo=true

#do not append the old file. Create a new log file everytime

log4j.appender.FILE.Append=false
 

#Prevent internal log4j DEBUG messages from polluting the output.

#log4j.logger.org.apache.log4j.PropertyConfigurator=INFO

#log4j.logger.org.apache.log4j.config.PropertySetter=INFO

#log4j.logger.org.apache.log4j.FileAppender=INFO