Apps

	What is Log : We need some information to be logged in the console, file or database   What is Log4j : Used for logging mechanism It is fast, flexible and reliable logging framework It is written by java and distributed under Apache Software License   Why Log4j Open source Can be used for small or large projects Possible to store the flow details of our selenium automation in a file, console or database   Log 4j Components Loggers : It is responsible for logging information. Create the instance of logger class Log4j levels : All - it will log everything DEBUG - print debugging information INFO - print info message that highlights the progress of apps - WARN - print infor regarding faulty and unexpected system behavior ERROR - print error message that might allows system to continue FATAL - print system critical info which cousing application to crsh OFF - no logging Appenders : used to deliver log Events to their destination ConsoleAppender - used to log standard output FileAppender - used to prints logs to some file RollingFileAppender - to a file with maximum size Layouts : It is responsible for formatting logging info in different styles   Steps to create log Download log4j jar files or get the dependecy if you are using maven project https://mvnrepository.com/artifact/log4j/log4j Place log4j.properties / log4j.xml file in project home directory ( only can be used) log4j.properties file Logger logg = Logger.getLogger("class_name"); PropertyConfigurator.configure("Log4j.properties") Log4j.xml file Logger logg = Logger.getLogger("class_name"); DOMConfigurator.configure("log4j.xml"); Create utility class (log) to initialize log4j logs Create base Class and configure ur log4j.xml using DOMConfigurator Write your test cases using test class     Steps to create for creating log 4j by automation step by step (Working) Add Log4j libraries in the java project Can add jar files or maven dependency https://logging.apache.org/log4j/2.x/maven-artifacts.html   Create reference for logger in the class Class where you want to add log statements   public class Log4jExample {   public static Logger logger = LogManager.getLogger(Log4jExample.class);   public static void main(String[] args) { System.out.println("\n  start --------------");   logger.info("this is information message"); logger.error("this is error message"); logger.warn("this is warn message"); logger.fatal("this is fatal message"); logger.trace("this is trace message"); System.out.println("\n  Completed --------------"); } }   Create log4j.xml or log4j.properties file  log4j.properties file : Create Log4j2.properties file in resource folder Copy file from https://springframework.guru/log4j-2-configuration-using-properties-file/ name=PropertiesConfig property.filename = logs appenders = console, file   appender.console.type = Console appender.console.name = STDOUT appender.console.layout.type = PatternLayout appender.console.layout.pattern = [%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n   appender.file.type = File appender.file.name = LOGFILE appender.file.fileName=${filename}/propertieslogs.log appender.file.layout.type=PatternLayout appender.file.layout.pattern=[%-5level] %d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %c{1} - %msg%n   loggers=file logger.file.name=learn.log4j  ///***change package name logger.file.level = trace logger.file.appenderRefs = file logger.file.appenderRef.file.ref = LOGFILE   rootLogger.level = trace rootLogger.appenderRefs = stdout rootLogger.appenderRef.stdout.ref = STDOUT   Tutorial : https://www.youtube.com/watch?v=rbuR9Q_55h4