java.lang.NoClassDefFoundError: ch/qos/logback/classic/spi/LoggingEvent

[Przemo T]

Hi guys,

I'm getting the following error from time to time. Usually under heavy load.

Using vertx 3.3.3.

Exception in thread "vert.x-acceptor-thread-0" java.lang.NoClassDefFoundError: ch/qos/logback/classic/spi/LoggingEvent

        at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:419)

        at ch.qos.logback.classic.Logger.filterAndLog_0_Or3Plus(Logger.java:383)

        at ch.qos.logback.classic.Logger.warn(Logger.java:692)

        at io.netty.util.internal.logging.Slf4JLogger.warn(Slf4JLogger.java:151)

        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:876)

        at java.lang.Thread.run(Thread.java:745)

I don't think I'm able to provide reproducer.

Anyone encountered something similar?

[Przemo T]

That error breaks acceptor thread. Problem has several aspects.

- The real problem seems to be "Too many open files" exception. I guess that explains why you need heavy load to reproduce.

- SingleThreadEventExecutor tries to log that exception but gets NoClassDefFoundError (though classes seems to be on classpath).

Probably found a workaround - to create instances of ch.qos.logback.classic.spi.LoggingEvent and ThrowableProxy before vertx is created. Need to take deeper look at classloading.

[Clement Escoffier]

Hi,

It looks like you have SLF4J in your classpath, so Netty uses SLF4J to log messages. However, slf4j is configured to use logback and logback is not in your classpath.

Clement

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[Jez P]

What OS are you running on? 

[Przemo T]

As I mentioned, I added workaround to created objects of missing classes before vertx is created. So the classes are there.

[Przemo T]

I'm running my java application in docker built from openjdk-8u102-jre image (Debian GNU/Linux 8 (jessie)).

Docker is running on Amazon Linux AMI (which I guess evolved from RHEL and CentOS).

I start my application as java process (java -jar ...). It is fat jar created by spring boot. Spring boot is configured to use logback (via logback-spring.xml). I also use lib logstash-logback-encoder to produce output in logstash json format.

I set property System.setProperty("vertx.logger-delegate-factory-class-name", "io.vertx.core.logging.SLF4JLogDelegateFactory").