log4j code example

Example 1: log4j maven

package com.howtodoinjava;
 
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!");
    }
}

Example 2: log4j

How do you use Log4J in your framework?
printing/logging the important events of the application/test run.
in my project I did logging using the log4j library.
I added the library dependency into pom.xml.
For logging we create an object from
Logger Interface and LogManager class using
getLogger method and passing the class name in it;  

private static Logger log = LogManager.getLogger(LogDemo.class.getName());
static Logger log = Logger.getLogger(log4jExample.class.getName());

We create it by passing the name of the current class.
Then we can use this object to do our logging.
log.info
log.debug
log.fatal
log.error

The Logger object is responsible for capturing 
logging information and they are stored in a namespace hierarchy.

Example 3: log4j example

import org.apache.log4j.Logger;

import java.io.*;
import java.sql.SQLException;
import java.util.*;

public class log4jExample{

   /* Get actual class name to be printed on */
   static Logger log = Logger.getLogger(log4jExample.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");
   }
}

Example 4: log4j example

# Define the root logger with appender file
log = /usr/home/log4j
log4j.rootLogger = DEBUG, FILE

# Define the file appender
log4j.appender.FILE=org.apache.log4j.FileAppender
log4j.appender.FILE.File=${log}/log.out

# Define the layout for file appender
log4j.appender.FILE.layout=org.apache.log4j.PatternLayout
log4j.appender.FILE.layout.conversionPattern=%m%n