Add log file for console java program using log4j

UPLupdateSysProperties.log

2018-06-07 11:56:53 INFO  UPLupdateSysProperties:12 - Sample info message 2018-06-07 11:56:53 WARN  UPLupdateSysProperties:13 - Sample warn message 2018-06-07 11:56:53 ERROR UPLupdateSysProperties:14 - Sample error message 2018-06-07 11:56:53 FATAL UPLupdateSysProperties:15 - Sample fatal message 2018-06-07 12:10:49 INFO  UPLupdateSysProperties:12 - Sample info message 2018-06-07 12:10:49 WARN  UPLupdateSysProperties:13 - Sample warn message 2018-06-07 12:10:49 ERROR UPLupdateSysProperties:14 - Sample error message 2018-06-07 12:10:49 FATAL UPLupdateSysProperties:15 - Sample fatal message

Create java project and class. Put files log4j.properties and log4j.jar in "src" folder and add jar reference in build path.

modify log file location in file log4j.properties 
log4j.appender.file.File=D:\\Logs\\UPLupdateSysProperties.log

This will create folder/s (if not exists), log file at specified location. 
Whenever program get executed, new messages will get appended in log file.


UPLupdateSysProperties.java

package com.upl.utility; import org.apache.log4j.Logger; public class UPLupdateSysProperties {        final static Logger logger = Logger.getLogger(UPLupdateSysProperties.class);               public static void main(String[] args){                       logger.debug("Sample debug message");         logger.info("Sample info message");         logger.warn("Sample warn message");         logger.error("Sample error message");         logger.fatal("Sample fatal message");                       System.out.println("dbc1");        } }

log4j.properties

# Root logger option log4j.rootLogger=INFO, stdout, file # Redirect log messages to console log4j.appender.stdout=org.apache.log4j.ConsoleAppender # log4j.appender.stdout.Target=System.out log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n # Redirect log messages to a log file, support file rolling. log4j.appender.file=org.apache.log4j.RollingFileAppender log4j.appender.file.File=D:\\Logs\\UPLupdateSysProperties.log log4j.appender.file.MaxFileSize=5MB log4j.appender.file.MaxBackupIndex=10 log4j.appender.file.layout=org.apache.log4j.PatternLayout log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

Output

2018-06-07 12:27:32 INFO  UPLupdateSysProperties:12 - Sample info message 2018-06-07 12:27:32 WARN  UPLupdateSysProperties:13 - Sample warn message 2018-06-07 12:27:32 ERROR UPLupdateSysProperties:14 - Sample error message 2018-06-07 12:27:32 FATAL UPLupdateSysProperties:15 - Sample fatal message dbc1