Change location of log4j.properties

I want to put all my config files in a /config subfolder of my application directory. Log4j is expecting the log4j.properties file in the root folder of my application. Is there a way to tell log4j where to look for the properties file?

Yes, define log4j.configuration property

java -Dlog4j.configuration=file:/path/to/log4j.properties myApp

Note, that property value must be a URL.

For more read section 'Default Initialization Procedure' in Log4j manual.

You can use PropertyConfigurator to load your log4j.properties wherever it is located in the disk.

Example:

Logger logger = Logger.getLogger(this.getClass());
String log4JPropertyFile = "C:/this/is/my/config/path/log4j.properties";
Properties p = new Properties();

try {
	p.load(new FileInputStream(log4JPropertyFile));
	PropertyConfigurator.configure(p);
	logger.info("Wow! I'm configured!");
} catch (IOException e) {
	//DAMN! I'm not....
	
}

If you have an XML Log4J configuration, use DOMConfigurator instead.

Use the PropertyConfigurator: PropertyConfigurator.configure(configFileUrl);

Refer to this example taken from - http://www.dzone.com/tutorials/java/log4j/sample-log4j-properties-file-configuration-1.html

import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

public class HelloWorld {

	static final Logger logger = Logger.getLogger(HelloWorld.class);
    static final String path = "src/resources/log4j.properties";
	
	public static void main(String[] args) {

		PropertyConfigurator.configure(path);
		logger.debug("Sample debug message");
		logger.info("Sample info message");
		logger.warn("Sample warn message");
		logger.error("Sample error message");
		logger.fatal("Sample fatal message");
	}
}

To change the logger levels - Logger.getRootLogger().setLevel(Level.INFO);

In Eclipse you can set a VM argument to:

-Dlog4j.configuration=file:///${workspace_loc:/MyProject/log4j-full-debug.properties}

This is my class : Path is fine and properties is loaded.

package com.fiserv.dl.idp.logging;

import java.io.File;
import java.io.FileInputStream;
import java.util.MissingResourceException;
import java.util.Properties;

import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

public class LoggingCapsule {
	
	private static Logger logger = Logger.getLogger(LoggingCapsule.class);
	
	public static void info(String message) {
		
		
		try {
			
			String configDir = System.getProperty("config.path");
            if (configDir == null) {
                throw new MissingResourceException("System property: config.path not set", "", "");
            }
            Properties properties = new Properties();
            properties.load(new FileInputStream(configDir + File.separator + "log4j" + ".properties"));
			PropertyConfigurator.configure(properties);
		} catch (Exception e) {
			e.printStackTrace();

		}
		logger.info(message);
	}
	public static void error(String message){
		System.out.println(message);
	}

}

You must use log4j.configuration property like this:

java -Dlog4j.configuration=file:/path/to/log4j.properties myApp

If the file is under the class-path (inside ./src/main/resources/ folder), you can omit the file:// protocol:

java -Dlog4j.configuration=path/to/log4j.properties myApp