Log4j is a simple and flexible logging framework. Logging equips the developer with detailed context for application failures. With log4j it is possible to enable logging at runtime without modifying the application binary. The log4j package is designed so that these statements can remain in shipped code without incurring a heavy performance cost.
Below are the most basic steps to configure log4j logging support in your project.
1) Create a maven project
mvn archetype:generate -DgroupId=com.howtodoinjava -DartifactId=Log4jTestProject -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false
Run above command in your eclipse workspace or any other IDE you are working in. If you already have a project in your workspace, then directly go to step 3.
2) Convert the project to eclipse supported java project
mvn eclipse:eclipse
Above command will convert maven project to eclipse java project. Now, import the project to eclipse.
3) Update pom.xml file with log4j dependencies
Add below given dependencies to pom.xml.
<dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency>
Run below command to download required jars in your local system and update project runtime dependencies also.
mvn eclipse:eclipse
4) Test the application with BasicConfigurator
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!");
}
}
Output:
0 [main] DEBUG com.howtodoinjava.Log4jHelloWorld - Hello World!
If you saw above message in your console then congrats, we have successfully configured log4j. If you have any problem the repeat all above steps again or drop me a comment.
Happy Learning !!
Tom Moyer
Please fix the problem first pointed out by Steve Nov 8’th 2012. Your step 3, lines 2 and 3 both need to have two instance of the currently shown as lower case i (the I in Id in groupId and in artifactId) as upper case. The lower case i’s you have cause 4 errors
1) The groupId can not be empty
2)’dependencies.dependency.groupId’ for null:log4j:jar is missing
and a similar pair for the artifactId
Lokesh Gupta
Sorry for the delay. Updated the post.
shmehta21@gmail.com
Hi Lokesh,
I did the setup for Maven and after running Maven command as said in step 1.), i got the below error:
[ERROR] No plugin found for prefix ‘archetype’ in the current project and in the
plugin groups [org.apache.maven.plugins, org.codehaus.mojo] available from the
repositories [local (C:UsersSagarMe.m2repository), central
n.apache.org/maven2)] -> [Help 1]
[ERROR] [Help 1] https://cwiki.apache.org/confluence/display/MAVEN/NoPluginFoundF
orPrefixException
However, I could see some plugings getting downloaded in my .m2 folder
Lokesh Gupta
Paste your pom.xml file here in code tags.
Steve
good post – couple of typos’…..see below
1.
2.log4j (should be groupId)
3.log4j (should be artifactId)
4.1.2.17
5.