LOG4J: no Appenders could be found for logger

I        Issue : Getting warning message as below

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            log4j:WARN No appenders could be found for logger (LoggerCode.UnderstandLogger).

            log4j:WARN Please initialize the log4j system properly.

             log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

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               Fix :    

Ø           To resolve above issue we need to implement Logging in our framework or class.

Ø              Define the root logger properly based on the levels and syntax given below

l            log4j.rootLogger = FATAL, FILE

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1.       So basically Log4j has three major components

Ø  Loggers

Ø  Appenders / Handlers

Ø  Layouts / Formatters 

2.       All above mentioned components are basically work together to enable dev/QA to log message accordingly based on the message type and levels also formatting and location where we can see these logs.

3.       Advantage of using logger over plain System.out.println is to categories the logging based on some specific criteria/type or level you can say.

4.       Generally we have three questions in mind while working with logger.

Ø  How to log

o In Appenders with the help of Formatters

Ø  What to log

o Based on logger function and level define in the log4j.config file

Ø  Where to log

o Appender -console/File

 

Levels and visibility in Log4j
	1. ALL	2. TRACE	3. DEBUG	4. INFO	5. WARN	6. ERROR	7. FATAL
1. ALL	Yes	Yes	Yes	Yes	Yes	Yes	Yes
2. TRACE		Yes	Yes	Yes	Yes	Yes	Yes
3. DEBUG			Yes	Yes	Yes	Yes	Yes
4. INFO				Yes	Yes	Yes	Yes
5. WARN					Yes	Yes	Yes
6. ERROR						Yes	Yes
7. FATAL							Yes
8. OFF

 

Based on the above table lets understand how we can set the levels in logger.

If in the configuration file we set Log4j.rootLogger =  Debug it will Log all the values related to levels which are lesser then it like Info, Warn, error etc.

But let suppose if you set Log4j.rootLogger =  Error and try to log the values using debug , info and warn appender it will not log these informations.

This is how we can control the levels of logging

 

Log4j.Properties file

# Define the root logger with appender file

# where you want to log the data while

log = C:/Users/test/Music/Batch-Feb-2021/Online/Selenium/src/results/

# Define the root logger and level of logging

log4j.rootLogger = FATAL, FILE

 

# Define the file appender

log4j.appender.FILE=org.apache.log4j.RollingFileAppender

# Rolling file appender is a child class of file appender file to take the back of log file when they reach to certain size in below lines you can see size is defined with backup index

 

log4j.appender.FILE.File=${log}/logs.out

log4j.appender.FILE.MaxFileSize=5MB

log4j.appender.FILE.MaxBackupIndex=3

 

# Define the layout for file appender

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

# Define to print the log value with IST timestamp

log4j.appender.FILE.layout.ConversionPattern=%d{dd/MM/yyyy HH:mm:ss} %c %m%n

 

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

log4j.appender.dest1.Append=true

 

Java Program Code

package LoggerCode;

import org.apache.log4j.Logger;

public class UnderstandLogger {

static Logger log = Logger.getLogger(UnderstandLogger.class.getName());

public static void main(String[] args) {

        log.debug("Hello this is a debug message");

log.info("Hello this is an info message");

log.trace("failed");  

}

}