Starting executable war with -Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager produces a ClassNotFoundException

[electricsam]

I would like to use Log4j2 as the logging implementation. As per the documentation here: https://docs.spring.io/spring-boot/docs/current/reference/html/howto-logging.html#howto-configure-log4j-for-logging, I have set the following system property: -Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager.

The following error is printed at startup:

Could not load Logmanager "org.apache.logging.log4j.jul.LogManager"
java.lang.ClassNotFoundException: org.apache.logging.log4j.jul.LogManager
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:93)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.util.logging.LogManager$1.run(LogManager.java:195)
	at java.util.logging.LogManager$1.run(LogManager.java:181)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.util.logging.LogManager.<clinit>(LogManager.java:181)
	at java.util.logging.Logger.demandLogger(Logger.java:448)
	at java.util.logging.Logger.getLogger(Logger.java:502)
	at com.sun.jmx.remote.util.ClassLogger.<init>(ClassLogger.java:55)
	at javax.management.NotificationBroadcasterSupport.<clinit>(NotificationBroadcasterSupport.java:365)
	at javax.management.MBeanServerDelegate.<init>(MBeanServerDelegate.java:72)
	at com.sun.jmx.mbeanserver.MBeanServerDelegateImpl.<init>(MBeanServerDelegateImpl.java:100)
	at com.sun.jmx.mbeanserver.JmxMBeanServer.newMBeanServerDelegate(JmxMBeanServer.java:1374)
	at javax.management.MBeanServerBuilder.newMBeanServerDelegate(MBeanServerBuilder.java:66)
	at javax.management.MBeanServerFactory.newMBeanServer(MBeanServerFactory.java:321)
	at javax.management.MBeanServerFactory.createMBeanServer(MBeanServerFactory.java:231)
	at javax.management.MBeanServerFactory.createMBeanServer(MBeanServerFactory.java:192)
	at java.lang.management.ManagementFactory.getPlatformMBeanServer(ManagementFactory.java:469)
	at org.apache.logging.log4j.core.jmx.Server.reregisterMBeansAfterReconfigure(Server.java:139)
	at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:556)
	at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:617)
	at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:634)
	at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:229)
	at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:153)
	at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
	at org.apache.logging.log4j.LogManager.getContext(LogManager.java:194)
	at org.apache.commons.logging.LogFactory$Log4jLog.<clinit>(LogFactory.java:199)
	at org.apache.commons.logging.LogFactory$Log4jDelegate.createLog(LogFactory.java:166)
	at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:109)
	at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:99)
	at org.springframework.boot.SpringApplication.<clinit>(SpringApplication.java:198)
	at com.example.Application.main(Application.java:10)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
	at org.springframework.boot.loader.WarLauncher.main(WarLauncher.java:58)

Attached is a sample project that demonstrates the problem. Build it with "mvn package", unzip the log4j-war-example-1.0.0-SNAPSHOT.zip and run bin/run.sh.

I am using Spring Boot 2.0.0.

log4j-war-example.zip

[philwebb]

Looks like we're either missing a dependency or our documentation needs updating. Try adding the following to your POM:

<dependency>
	<groupId>org.apache.logging.log4j</groupId>
	<artifactId>log4j-jul</artifactId>
</dependency>

[philwebb]

See #11660 which added that documentation. I wonder if there's any problem adding the dependency to the starter?

[electricsam]

@philwebb Adding that dependency to my pom worked.

[wilkinsona]

I can't recall if we considered adding log4j-jul to the starter when we looked at #11660. The jar's only 24KB and I don't think it has any effect without the system property. There aren't any problems with adding it to the starter that I can see.

[philwebb]

I think we should add it since it's only 24kb.

[mkrawetko]

still getting exception with spring boot 2.0.3.RELEASE:

Could not load Logmanager "org.apache.logging.log4j.jul.LogManager"
java.lang.ClassNotFoundException: org.apache.logging.log4j.jul.LogManager
        at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at java.util.logging.LogManager$1.run(LogManager.java:195)
        at java.util.logging.LogManager$1.run(LogManager.java:181)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.util.logging.LogManager.<clinit>(LogManager.java:181)
        at java.util.logging.Logger.demandLogger(Logger.java:448)
        at java.util.logging.Logger.getLogger(Logger.java:502)
        at com.sun.jmx.remote.util.ClassLogger.<init>(ClassLogger.java:55)
        at sun.management.jmxremote.ConnectorBootstrap.<clinit>(ConnectorBootstrap.java:814)
        at sun.management.Agent.startAgent(Agent.java:257)
        at sun.management.Agent.startAgent(Agent.java:447)

adding dependency doesn't help :(

<dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-jul</artifactId>
        </dependency>

[wilkinsona]

As shown by the stack trace, that's a different problem to the one reported in this issue.

In your case, Log4j needs to be available to the system class loader rather than the launcher class loader that Boot creates from the contents of BOOT-INF/lib. One way to achieve that would be to package Log4j's classes in the root of the jar. That's currently not as easy as we'd like it to be when using Maven (#6626). It's quite a bit easier with Gradle.