Spring Boot Log4j2.xml Example

Spring boot’s default logging uses Logback which is included as a transitive dependency. Spring Boot supports Log4j2 for logging configuration if it is on the classpath and Logback is excluded.

To configure Log4j2 with Spring Boot2, follow these two simple steps:

1. Log4j2 Maven Dependency

In fact, it is two steps change. First, remove spring’s default spring-boot-starter-logging starter dependency which excludes Logback from the classpath. Then add the spring-boot-starter-log4j2 starter dependency.

 <dependencies>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
    <exclusions>
      <exclusion>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-logging</artifactId>
      </exclusion>
    </exclusions>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-log4j2</artifactId>
  </dependency>
</dependencies>

2. Add log4j2.xml File in /resources Folder

Spring will automatically configure log4j2 once it finds its jar files in the classpath. Now we have to add log4j2.xml or (log4j2.properties) in src/main/resources folder. That’s all.

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="30">
    <Properties>
        <Property name="LOG_PATTERN">%d{yyyy-MM-dd'T'HH:mm:ss.SSSZ} %p %m%n</Property>
        <Property name="APP_LOG_ROOT">c:/temp</Property>
    </Properties>

    <Appenders>
        <Console name="Console" target="SYSTEM_OUT" follow="true">
            <PatternLayout pattern="${LOG_PATTERN}" />
        </Console>
        <RollingFile name="appLog"
                fileName="${APP_LOG_ROOT}/SpringBoot2App/application.log"
                filePattern="${APP_LOG_ROOT}/SpringBoot2App/application-%d{yyyy-MM-dd}-%i.log">
            <PatternLayout pattern="${LOG_PATTERN}" />
            <Policies>
                <SizeBasedTriggeringPolicy size="19500KB" />
            </Policies>
            <DefaultRolloverStrategy max="1" />
        </RollingFile>
    </Appenders>

    <Loggers>
        <Logger name="com.howtodoinjava.app" additivity="false">
            <AppenderRef ref="appLog" />
            <AppenderRef ref="Console" />
        </Logger>
        <Root level="debug">
            <AppenderRef ref="Console" />
            <AppenderRef ref="appLog" />
        </Root>
    </Loggers>
</Configuration>

3. Demo

Now add a few log statements in the application and see the logs in configured appenders e.g. I configured console and file.

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.context.ApplicationContext;
 
@SpringBootApplication
public class Application extends SpringBootServletInitializer {
 
  private static final Logger LOGGER = LogManager.getLogger(Application.class);
 
  public static void main(String[] args)
    {
        ApplicationContext ctx = SpringApplication.run(Application.class, args);
         
        LOGGER.info("Info level log message");
        LOGGER.debug("Debug level log message");
        LOGGER.error("Error level log message");
    }
}

Check the output in the console and the log file.

2018-06-01T13:55:42.506+0530 INFO Info level log message
2018-06-01T13:55:42.506+0530 DEBUG Debug level log message
2018-06-01T13:55:42.506+0530 ERROR Error level log message

Let me know if you face any problems in this spring boot log4j2 example.

Happy Learning !!

Yaswanth

May 21, 2024 at 4:14 pm

How to configure for different environments in same file?
Reply
- Lokesh Gupta
  
  June 8, 2024 at 8:59 pm
  
  Please elaborate the problem.
  Reply
Rico

March 14, 2024 at 8:56 am

Hi, I’m using exactly the same dependency you got right now. If I want to customize the config filename to log4j2-spring.xml with setting logging.config=classpath: log4j2-spring.xml in application.properties, it doesn’t recognize the config file at all. I don’t know what’s wrong.
Reply
- Lokesh Gupta
  
  March 14, 2024 at 11:43 am
  
  1. Ensure that there are no spaces before or after the colon (:) in the file path.
  2. Enable debug logging to get more insights into what’s happening during the application startup with logging.level.org.springframework=DEBUG
  Reply
  - Rico
    
    March 14, 2024 at 12:37 pm
    
    I added logging.level.org.springframework=DEBUG, and remove ths space. Nothing was reported wrong while build.
    
    $ ./mvnw spring-boot:run
    Warning: JAVA_HOME environment variable is not set.
    [INFO] Scanning for projects…
    [INFO]
    [INFO] ———————-< com.wago:print-converter >———————-
    [INFO] Building print-converter 0.0.1-SNAPSHOT
    [INFO] from pom.xml
    [INFO] ——————————–[ jar ]———————————
    [INFO]
    [INFO] >>> spring-boot:3.2.3:run (default-cli) > test-compile @ print-converter >>>
    [INFO]
    [INFO] — resources:3.3.1:resources (default-resources) @ print-converter —
    [INFO] Copying 1 resource from src\main\resources to target\classes
    [INFO] Copying 1 resource from src\main\resources to target\classes
    [INFO]
    [INFO] — compiler:3.11.0:compile (default-compile) @ print-converter —
    [INFO] Nothing to compile – all classes are up to date
    [INFO]
    [INFO] — resources:3.3.1:testResources (default-testResources) @ print-converter —
    [INFO] skip non existing resourceDirectory C:\Projects\PrintConverter\src\test\resources
    [INFO]
    [INFO] — compiler:3.11.0:testCompile (default-testCompile) @ print-converter —
    [INFO] Nothing to compile – all classes are up to date
    [INFO]
    [INFO] <<< spring-boot:3.2.3:run (default-cli) < test-compile @ print-converter <<<
    [INFO]
    [INFO]
    [INFO] — spring-boot:3.2.3:run (default-cli) @ print-converter —
    [INFO] Attaching agents: []
    15:04:48.853 [main] ERROR com.wago.printconverter.PrintConverterApplication – Error loggggg message
    15:04:48.856 [main] ERROR com.wago.printconverter.PrintConverterApplication – Error log message
    [INFO] ————————————————————————
    [INFO] BUILD SUCCESS
    [INFO] ————————————————————————
    [INFO] Total time: 1.960 s
    [INFO] Finished at: 2024-03-14T15:04:48+08:00
    [INFO] ————————————————————————
    
    Here is my main.
    private final static Logger logger = LoggerFactory.getLogger(PrintConverterApplication.class);
    
    public static void main(String[] args) {
    
    // logger.info(System.getProperty(“java.class.path”));
    // SpringApplication.run(PrintConverterApplication.class, args);
    logger.error(“Error loggggg message”);
    logger.info(“PrintConverterApplication ended.”);
    logger.debug(“Debug log message”);
    logger.info(“Info log message”);
    logger.error(“Error log message”);
    }
    
    Only 2 log.error work without formatting.
    Reply
    - Lokesh Gupta
      
      March 15, 2024 at 1:13 pm
      
      If possible, can you submit the demo app with your code in a github repo?
      Reply
Sachin Raghav

October 15, 2022 at 10:02 pm

Hi, I am getting the below exception in spring Boot :
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/Users/sachin.raghav/ .m2/repository/org/apache/logging/log4j/log4j-slf4j-impl/2.17.0/log4j-slf4j-impl-2.17.0.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/Users/sachin.raghav/.m2/repository/ch/qos/logback/logback-classic /1.2.3/logback-classic-1.2.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html #multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.apache.logging.slf4j.Log4jLoggerFactory]
Exception in thread “main” java.lang.ExceptionInInitializerError
Caused by: org.apache.logging.log4j.LoggingException: log4j-slf4j-impl cannot be present with log4j-to-slf4j
at org.apache.logging.slf4j.Log4jLoggerFactory .validateContext(Log4jLoggerFactory.java:60)

please suggest a fix for the given issue.
Reply
- Lokesh Gupta
  
  October 15, 2022 at 11:21 pm
  
  You have log4j-slf4j-impl.jar and log4j-to-slf4j.jar, both in the classpath. Use maven dependency tree to find out which libraries are pulling them transitively and exclude one of two jars mentioned above.
  Reply

I am getting this problem and in the console and Info and error log is showing on console but debug line is not printing on console

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/1707393/.m2/repository/ ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/C:/Users/1707393/.m2/repository/ org/apache/logging/log4j/log4j-slf4j-impl/2.12.1/log4j-slf4j-impl-2.12.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See https://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [ch.qos.logback.classic.util.ContextSelectorStaticBinder]

Chehak

March 31, 2020 at 1:53 pm

In Springboot the default logging level is INFO which means info and higher logging levels be printed, like ERROR, WARN, FATAL etc but lower levels like DEBUG and TRACE wont be printed. Change the logging level to see DEBUG logs
Reply

Sayali

June 4, 2019 at 5:44 pm

log file is not generated.
Its only printed the log on console
Reply
- sunil
  
  October 27, 2019 at 11:59 am
  
  Same here, Just Writes the Logs to the Console but the log file doesnt gets generated.any extra configuration needed. let us know
  Reply
  - Lokesh Gupta
    
    October 15, 2022 at 11:25 pm
    
    Change <AppenderRef ref=”Console” /> to <AppenderRef ref=”appLog” /> in root appender.
    Reply
- Nibedita
  
  December 13, 2019 at 3:53 pm
  
  Same problem here. I am getting the log in console only not in the log file.
  Reply
Amit

February 13, 2019 at 11:02 pm

Thanks for such nice tutorial. Keep this site updated with new articles. This is my one of the best reference.
Reply
Anurag Chaturvedi

December 21, 2018 at 5:07 pm

Hi Getting below error while starting boot app

ERROR StatusLogger Log4j2 could not find a logging implementation. Please add log4j-core to the classpath. Using SimpleLogger to log to the console…

snippet:

org.springframework.boot
spring-boot-starter-web

org.springframework.boot
spring-boot-starter-logging

org.springframework.boot
spring-boot-starter-log4j2
Reply

Spring Boot Log4j2.xml Example

1. Log4j2 Maven Dependency

2. Add log4j2.xml File in /resources Folder

3. Demo

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