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Topic

7. Log4j

Outcome

You would be able to complete thelog4j In just 2 days. Just follow the steps with the help of the Technical coordinator.

Duration

2 Days

Task

1. Log4j is a reliable, fast and flexible logging framework (APIs) written in Java, which is distributed under the Apache Software License.

2. Log4j has been ported to the C, C++, C#, Perl, Python, Ruby, and Eiffel languages.

3.Log4j has three main components:
-> Loggers: Responsible for capturing logging information.
-> Appenders: Responsible for publishing logging information to various preferred destinations.
-> Layouts: Responsible for formatting logging information in different styles

4. Logger Object − The top-level layer of log4j architecture is the Logger which provides the Logger object.
The Logger object is responsible for capturing logging information.

5. Layout Object − The layout layer of log4j architecture provides objects which are used to format logging information in different styles.
It provides support to appender objects before publishing logging information.
Layout objects play an important role in publishing logging information in a way that is human-readable and reusable.

6. Appender Object − This is a lower-level layer of log4j architecture which provides Appender objects.
The Appender object is responsible for publishing logging information to various preferred destinations such as a database, file, console, UNIX Syslog, etc.

Following are the Pros and Cons of Logging

7. Logging is an important component of the software development.
-> A well-written logging code offers quick debugging, easy maintenance, and structured storage of an applications runtime information.

8. Logging does have its drawbacks also. It can slow down an application.
-> If too verbose, it can cause scrolling blindness. To alleviate these concerns, log4j is designed to be reliable, fast and extensible.

9. the log4j API strives to be simple to understand and to use. -> The log4j.properties file is a log4j configuration file which keeps properties in key-value pairs.
-> By default, the LogManager looks for a file named log4j.properties in the CLASSPATH.

Logger

11. it is used to logging the information. If you implement the logger into our project.
Create an instance of logger class and it conations five log levels.

12. -> All – It will log everything
-> DEBUG – it will print the debug information
-> INFO – it will print the information message
-> ERROR – it will print the error message
-> FATAL – it will print the systems critical information message
-> OFF – No logging information message

Layout

12. It is responsible for formatting the logging information in different styles.

13. Validate the defects fixed and assigned back to you, close or reopen them as per the functionality.

Log4j Configuration

14. Step1: Create a maven project

15. Step2: Download the log4j maven dependency

16. Step3: Configure Log4j

17. package com.brightit;
import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;
public class Log4jHelloWorld {
static final Logger logger = Logger.getLogger(Log4jHelloWorld.class);
public static void main(String[] args)
{ //Configure logger
BasicConfigurator.configure();
logger.debug("Hello World!");
} }

18. Output:
-> 0 [main] DEBUG com.brightit.Log4jHelloWorld - Hello World!

19.Log4j Properties:
log4j.rootLogger=DEBUG/All/ERROR/OFF, file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=D:\\Jala\\Jobs\\Selenium.logs
log4j.appender.file.maxFileSize=400KB
log4j.appender.file.maxBackupIndex=5
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d - %5p - %c - %L - %m%n

19. Example 1 :
Class HelloWorld{
Public static void main(String args[]){
public Logger logger = Logger.getLogger(HelloWorld.class);
logger.info(“hello”);
int a = 10;
int b = 20;
try{ logger.error(“Before error”);
c=a/b; logger.error(“After error”);
}
catch(Exception e){
System.out.println(e);
} System.out.println(c);
} }

20. Log4j Properties:
log4j.rootLogger = All,Jala
log4j.appender.Jala = org.apache.log4j.FileAppender
log4j.appender.Jala.File = log4j.log
log4j.appender.Jala.layout = org.apache.log4j.PatternLayout
log4j.appender.Jala.laout.ConversionPattern = %4d - %c -%C - %L

21. Example 2 :
import org.apache.log4j.Logger;
import java.io.*;
import java.sql.SQLException;
import java.util.*;
public class Example{
/* Get the class name to be printed on */
static Logger log = Logger.getLogger(Example.class.getName());
public static void main(String[] args)throws IOException,SQLException{
log.debug("Hello this is a debug message");
log.info("Hello this is an info message");
} }

Assignments

Contact the Technical Co-ordinator for Assignments. For any help WhatsApp the office number