How to Set Up Log4j2 Logging in Spring Boot Applications

What are the steps to configure Log4j2 logging in a Spring Boot application?

# application.properties
logging.config=classpath:log4j2.xml

Log4j2 is a powerful logging framework that offers more features and better performance compared to the default logging framework used in Spring Boot (which is Logback). Configuring Log4j2 in a Spring Boot application enhances logging capabilities and allows for flexible logging configurations.

<Configuration>
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1} - %m%n" />
        </Console>
    </Appenders>
  <Loggers>
        <Root level="info">
            <AppenderRef ref="Console" />
        </Root>
    </Loggers>
</Configuration>

Causes

• Using the default logging framework, which is not as powerful as Log4j2.
• Misconfigurations in the logging.properties or application.yml file that lead to logging issues.

Solutions

• Update your Spring Boot project dependencies to include Log4j2 by adding the required Maven or Gradle dependencies.
• Create a log4j2.xml configuration file in the resources folder to define your logging settings.
• Specify the configuration location in your application.properties or application.yml file using `logging.config` property.

Mistake: Not including the necessary dependencies for Log4j2 in your build file.

Solution: Ensure you add dependencies for 'log4j-api', 'log4j-core', and 'log4j-slf4j-impl' in your Maven or Gradle build file.

Mistake: Forgetting to create a log4j2.xml file for configuration.

Solution: Always create a log4j2.xml file in the resources folder to define logging details.

Mistake: Using conflicting logging configurations from Spring Boot and Log4j2.

Solution: Set the logging.config property in application.properties to point to your log4j2.xml file.