Selenium Framework for Beginners 14 | What is Log4j | How to add Log4j in java project

Today we will learn What is Log4j and How to use it
1 What is Log4j
2 How to implement Log4j in Java Project

helpful tips

What is Log4j

Log4j is a java based logging framework
Is simple, flexible, reliable and fast
Is configured through a configuration file

Practical Example

Step 1:Add Log4j libraries in the java project
Can add jar files or maven dependency

Step 2 : Create reference for Logger in the class
Class where you want to add log statements

What is the difference ?

Step 4 : Run and Validate

Log4j - log levels

TRACE
Most detailed information. Expect these to be written to logs only. Since version 1.2.12

DEBUG
Detailed information on the flow through the system. Expect these to be written to logs only. Generally speaking, most lines logged by your application should be written as DEBUG

INFO
Interesting runtime events (startup/shutdown). Expect these to be immediately visible on a console, so be conservative and keep to a minimum.

WARN
Use of deprecated APIs, poor use of API, 'almost' errors, other runtime situations that are undesirable or unexpected, but not necessarily "wrong". Expect these to be immediately visible on a status console.

ERROR
Other runtime errors or unexpected conditions. Expect these to be immediately visible on a status console.

FATAL
Severe errors that cause premature termination. Expect these to be immediately visible on a status console.

OFF
The highest possible rank and is intended to turn off logging.

** built-in log levels with increasing order of severity

helpful tips

You can configure to append or overwrite logs in file

You can set logging OFF when not required
in case heavy logging is making your runs slower...

Log4j - Configuration File

Log4j is configured through a configuration file

Configuration files can be written in XML, JSON, YAML, or properties file format

Set of key-value pairs

Within a configuration you can define three main components:
Loggers
Appenders
Layouts

Configuring logging via a file has the advantage that logging can be turned on or off without modifying the application that uses Log4j.

Log4j - FAQ

Written in Java | Cross platform

part of the Apache Logging Services

initial release - January 8, 2001

On August 5, 2015 the Apache Logging Services Project Management Committee announced that Log4j 1 had reached end of life and that users of Log4j 1 are recommended to upgrade to Apache Log4j 2.

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Raghav

[onkardhavale]

seriously sir your tutorial got me out from 24 hrs wasted on checking from every where but your simple method solve my trouble of log 4j2 just 20 minutes thank you so much

[nadiyagone]

Am tied up watching all log4j videos and didn't any solution for making log 4j in maven project. But from this video I was successfully created logs without any errors. Thank you so much for making this video sir....

[NPRBEST]

Best tutorial for log4j on internet. Explained with great details...no doubts...

[Nstyleonlineuk]

just perfect ! clean and tidy explanation !thank you very much!

[virendrasinghbais]

You never disappoint.
Thanks and keep posting more.
Try covering end to end development videos

[Mostafizur_rahman]

This is exactly what I was looking for. This playlist is very helpful, helped me to PRACTICE before going out for interview. But in my opinion, this is not a beginner

[brucemyklebust]

thank you! this is exactly the video I was looking for

[jaquelinecuatepitzibastida]

THE BEST VIDEO I HAVE SEEN ON THE SUBJECT!!
Thank you very much, it has helped me a lot.
The entire playlist is a gem.

[sridharmamidipaka]

Very good bro
Do more and more and boostup us

[shehlaabdullah]

Thank you so much ..we learn alot of thing about automation .. really appreciate sir ...

[ashwinireddy]

As usual ver y well explained and never disappointed, I have been following your tutorials for my new job trials.

[kamaljitxSingh]

Hi raghav, You have explained in very neat manner, especially at the end of the video. Thanks, this will be very useful for me in company.

[ahsan]

Hi Raghav,
First thanks for all efforts for us.
I am facing a issue. As following this clip Log file is getting generate in logs folder but logs are not getting append inside the file. It show blank, where as logs are showing on console. Please guide on this. Thanks.

[deviyadlapalli]

Very neat and clear explanation thanks for your help..

[lucylucy]

It's a very detailed explanations thank you.

[rhacker]

Hi Raghav, thanks a lot !!
The information you provided will enough to rock the technology..
Thanks once again 😃..

[brandonflorida]

Beautifully clear. Thank you so much!

[sumam]

13:46 Very important part. If you don't put package name after "logger.file.name=", your log file will come out empty!

[dineshkmr]

Thank you so so much for this video ... it works flawlessly

[EliasHossein]

I will say just amazing explanation....