Redirect Jersey JUL logging to Log4j2

Question

I need to redirect Jersey request/response log to my log4j2.

I have Jersey logging enabled by using this code on my ApplicationJAXRS extends Application :

@Override
public Set<Class<?>> getClasses() {
    return new HashSet<Class<?>>() {{
        add(LoggingFilter.class);
    }};
    }

It seems that Jersey uses JUL (Java Logging) internally and the default output is STDOUT. At this moment I can see the STDOUT on Eclipse Console.

The Log4j2 documentation have a section about JDK Logging Adapter . It says

To use the JDK Logging Adapter, you must set the system property java.util.logging.manager to org.apache.logging.log4j.jul.LogManager

This must be done either through the command line (ie, using the -Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager argument) or by using System.setProperty() before any calls are made to LogManager or Logger.

To call the System.setProperty(*) before any Logger call I've tried to put it on a @PostConstruct in my Aplication class.

@PostConstruct
    public void init() {
        System.setProperty("java.util.logging.manager", "org.apache.logging.log4j.jul.LogManager");
    }

I could get it to log on my logging files.

This is my log4j2.xml:

    <Appenders>
        <RollingFile name="RollingFile" fileName="${log-path}/${name}.log" 
            filePattern="${log-path}/${date:yyyy-MM}/${name}-%d{yyyy-MM-dd}-%i.log">
            <PatternLayout>
                <Pattern>%d{dd-MM-yy HH:mm:ss,SSS} %-5p [%t] (%F:%L) - %m%n</Pattern>
            </PatternLayout>
            <Policies>
                <TimeBasedTriggeringPolicy interval="1" modulate="true"/>
            </Policies>
            <DefaultRolloverStrategy max="10" />
        </RollingFile>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d %-5p [%t] %C{2} (%F:%L) - %m%n" />
        </Console>
    </Appenders>
    <Loggers>
        <Root level="debug">
            <AppenderRef ref="Console" level="debug"/>
            <AppenderRef ref="RollingFile" level="debug"/>
        </Root>
    </Loggers>
</Configuration>

Answer 1

I would imagine that you have to set the system property at launch . Add code to your init method to see if setting the system property worked.

@PostConstruct
public void init() {
    String cn = "org.apache.logging.log4j.jul.LogManager";
    System.setProperty("java.util.logging.manager", cn);
    LogManager lm = LogManager.getLogManager();
    if (!cn.equals(lm.getClass().getName())) {
       try {
           ClassLoader.getSystemClassLoader().loadClass(cn);
       } catch (ClassNotFoundException cnfe) {
          throw new IllegalStateException("Jars not in system class path.", cnfe);
       }
       throw new IllegalStateException("Found " + lm.getClass().getName() + " set as launch param instead.");
    }
}

Answer 2

This actually works for the Jersey case though you still need to set the System property java.util.logging.manager=org.apache.logging.log4j.jul.LogManager

Instantiate your logger as normal for log4j2 for your general application logging. Then, explicitly instantiate a java.util.logging.Logger using org.apache.logging.log4j.jul.LogManager. This second Logger instance is then used to register a new LoggingFilter as can be seen here, using Jersey 2 Client for this example (verbose naming for clarity):

org.apache.logging.log4j.Logger logger = org.apache.logging.log4j.LogManager.getLogger(this.getClass().getName());

java.util.logging.Logger jerseyLogger = org.apache.logging.log4j.jul.LogManager.getLogManager().getLogger(this.getClass().getName());

jerseyLogger.setLevel(java.util.logging.Level.SEVERE); //OPTIONAL

Client client = ClientBuilder.newClient();
client.register(new LoggingFilter(jerseyLogger, false));

logger.info("App logging uses the normal logger");

Now, calls to logger work as expected and all of Jersey's jul logging output is directed back into log4j2 appenders as expected.