O Log4j é um framework de log muito simples de configurar.

Configuração

pom.xml

<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>

log4j.properties

# Root logger option
log4j.rootLogger=WARN, stdout

# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n
log4j.appender.stdout.Target=System.out

Utilização

ClasseLog4j.java

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

public class ClasseLog4j {

   protected final Logger logger = LogManager.getLogger(getClass().getName());

    public void log() {
        logger.info("Info Log...");
        logger.error("Error Log...");
    }

Resultado

console

22:36:43,471 INFO  [ClasseLog4j] (http--0.0.0.0-8080-2) Info Log...
22:36:43,471 ERROR [ClasseLog4j] (http--0.0.0.0-8080-2) Error Log...