Simple logging with log4j

Getting the log4j jars using maven
The pom file

  1: <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  2:   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  3:   <modelVersion>4.0.0</modelVersion>
  4: 
  5:   <groupId>com.mycompany</groupId>
  6:   <artifactId>Log4jTest</artifactId>
  7:   <version>1.0-SNAPSHOT</version>
  8:   <packaging>jar</packaging>
  9:   <name>Log4jTest</name>
 10:   <url>http://maven.apache.org</url>
 11: 
 12:   <properties>
 13:     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 14:   </properties>
 15: 
 16:   <dependencies>
 17:    
 18:   <dependency>
 19:   <groupId>log4j</groupId>
 20:   <artifactId>log4j</artifactId>
 21:   <version>1.2.17</version>
 22:     </dependency>  
 23:   </dependencies>
 24: </project>
 25: 

The log4j configuration file.
Note: 2 appeanders are declared one for the output of logging into the console and one for output it to file.  
The appeanders to use in each call to logging are declared 

  1: <?xml version="1.0" encoding="UTF-8" ?>
  2: <!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
  3: <log4j:configuration xmlns:log4j='http://jakarta.apache.org/log4j/'>
  4: 
  5:     <appender name="default.file" class="org.apache.log4j.FileAppender">
  6:         <param name="file" value="/log/mylogfile.log" />
  7:          <param name="append" value="false" />
  8:         <param name="threshold" value="debug" />
  9:         <layout class="org.apache.log4j.PatternLayout">
 10:             <param name="ConversionPattern" value="%d{ISO8601} %-5p [%c{1}] - %m%n" />
 11:         </layout>
 12:     </appender>
 13: 
 14:     <appender name="default.console" class="org.apache.log4j.ConsoleAppender">
 15:         <param name="target" value="System.out" />
 16:         <param name="threshold" value="debug" />
 17:         <layout class="org.apache.log4j.PatternLayout">
 18:             <param name="ConversionPattern" value="%d{ISO8601} %-5p [%c{1}] - %m%n" />
 19:         </layout>
 20:     </appender>
 21:   
 22:     <root>
 23:       <priority value="info" />
 24:       <appender-ref ref="default.file" />      
 25:     <appender-ref ref="default.console" />
 26:       
 27:     </root>
 28: </log4j:configuration>

The main file
The main file the demonstarts the use of logging.
Note about the configuration laoding using the DomConfigurator object

  1: package com.mycompany.log4jtest;
  2: 
  3: import org.apache.log4j.LogManager;
  4: import org.apache.log4j.Logger;
  5: import org.apache.log4j.xml.DOMConfigurator;
  6: 
  7: public class App 
  8: {
  9:     private static Logger logger = LogManager.getLogger("myLogger");
 10:   
 11:     public static void main( String[] args )
 12:     {
 13:         DOMConfigurator.configure("log4j.xml");
 14:         logger.info("This is an info!");
 15:         logger.error("This is an error!");
 16:         System.out.println( "Done!" );
 17:     }
 18: }
 19: 

The output
------------------------------------------------------------------------
Building Log4jTest 1.0-SNAPSHOT
------------------------------------------------------------------------

[resources:resources]
[debug] execute contextualize
Using 'UTF-8' encoding to copy filtered resources.
skip non existing resourceDirectory I:\Learn\java\Log4jTest\src\main\resources

[compiler:compile]
Compiling 1 source file to I:\Learn\java\Log4jTest\target\classes

[exec:exec]
2013-06-01 22:48:06,945 INFO  [myLogger] - This is an info!
2013-06-01 22:48:06,946 ERROR [myLogger] - This is an error!
Done!
------------------------------------------------------------------------
BUILD SUCCESS
------------------------------------------------------------------------
Total time: 1.313s
Finished at: Sat Jun 01 22:48:06 IDT 2013
Final Memory: 6M/15M
------------------------------------------------------------------------

sources
http://stackoverflow.com/questions/6358836/log4j-how-to-configure-simplest-possible-file-logging
http://www.dzone.com/tutorials/java/log4j/log4j-file-appender-example-1.html