Logging framework - SLF4J (Simple Logging Facade for Java)

Maven dependency (version managed by related BoM maven project pom.xml)

<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-api</artifactId>
</dependency>

How to use

// import required classes
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
 
// define logger
private static final Logger LOGGER = LoggerFactory.getLogger(AuthenticationServiceImpl.class);
 
// use in code
try {
// logic
} catch (final StorageException e) {
	final String message = "(" + accountId + ") fail.";
	LOGGER.error(message, e);
	throw new AuthenticationServiceException(message, e);
}

FATAL logging level (marker usage example)

// import utility
import net.bolbat.utils.logging.LoggingUtils;
 
// use in code
try {
// logic
} catch (final ManagerException e) {
	final String message = "Can't initialize persistence service.";
	LOGGER.error(LoggingUtils.FATAL, message, e);
	throw new ServiceInstantiationException(message, e);
}

SLF4J API implementations

  • default no-operation (NOP) logger, included in slf4j-api

  • logback (version managed by our maven parent project pom.xml)

     <dependency>
	<groupId>ch.qos.logback</groupId>
	<artifactId>logback-classic</artifactId>
</dependency>

  • apache log4j (version managed by our maven parent project pom.xml)

    <dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-log4j12</artifactId>
</dependency>

  • apache commons-logging (version managed by our maven parent project pom.xml) 

    <dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-jcl</artifactId>
</dependency>

  • java util logging (version managed by our maven parent project pom.xml) 

    <dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-jdk14</artifactId>
</dependency>

How to use for JUnit's without real dependency to logger implementation (logback example)

  • Add maven dependency only for testing scope (version managed by our maven parent project pom.xml) 

    <dependency>
	<groupId>ch.qos.logback</groupId>
	<artifactId>logback-classic</artifactId>
	<scope>test</scope>
</dependency>

  • Configure logger (example configuration)

Logging redirection from other loggers to SLF4J (just add required dependency)

  • apache log4j 

    <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>log4j-over-slf4j</artifactId>
    <version>1.7.5</version>
</dependency>

  • apache commons-logging 

    <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>jcl-over-slf4j</artifactId>
    <version>1.7.5</version>
</dependency>

  • java util logging 

    <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>jul-to-slf4j</artifactId>
    <version>1.7.5</version>
</dependency>
  • details can be found on http://www.slf4j.org/legacy.html

 

 

 

 

 

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