Java 21 error with LMAX

[jkvargas]

Description

While using amazon correto 21 and running the following line:
final static Logger logger = LogManager.getLogger();

I guess it is related to LMAX...

Configuration

Version: 2.21

Operating system: Linux

JDK: correto 21

Logs

Exception in thread "main" java.lang.NoClassDefFoundError: sun/misc/Unsafe
    at com.lmax.disruptor.util.Util$1.run(Util.java:103)
    at com.lmax.disruptor.util.Util$1.run(Util.java:100)
    at java.base/java.security.AccessController.doPrivileged(Unknown Source)
    at com.lmax.disruptor.util.Util.<clinit>(Util.java:109)
    at com.lmax.disruptor.RingBufferFields.<clinit>(RingBuffer.java:34)
    at com.lmax.disruptor.dsl.Disruptor.<init>(Disruptor.java:137)
    at org.apache.logging.log4j.core.async.AsyncLoggerConfigDisruptor.start(AsyncLoggerConfigDisruptor.java:220)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:312)
    at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:621)
    at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:694)
    at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:711)
    at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:253)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:155)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:47)
    at org.apache.logging.log4j.LogManager.getContext(LogManager.java:196)
    at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:599)
    at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:585)
    at Main.<clinit>(Main.java:25)
Caused by: java.lang.ClassNotFoundException: sun.misc.Unsafe
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(Unknown Source)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(Unknown Source)
    at java.base/java.lang.ClassLoader.loadClass(Unknown Source)

[jvz]

Might be related to #1829.

[jvz]

This might show up elsewhere in Log4j, actually, so it's not entirely solved by an LMAX upgrade here. This issue can be expanded to any other sun.misc.Unsafe usage (I'm pretty sure the mmap appender uses it amongst others).

Update: only other place is in MemoryMappedFileManager. The LMAX issue is hopefully solved by an update in LMAX.

[jkvargas]

hi @jvz ,
I am trying to reproduce the issue with the smallest app possible running on ubuntu linux with java 21 and version 2.+

app is quite simple:

package reproduce;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class App {
    private static Logger logger = LogManager.getLogger();

    public static void main(String[] args) {
        logger.info("test");
    }
}

and this is the config file.

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <Appenders>
        <!-- Define a Console appender -->
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
        </Console>
    </Appenders>

    <!-- Use the AsyncAppender as the root logger -->
    <Loggers>
        <AsyncRoot level="WARN">
            <AppenderRef ref="Console"/>
        </AsyncRoot>
        <AsyncLogger level="info" includeLocation="true">
            <AppenderRef ref="Console"/>
        </AsyncLogger>
    </Loggers>
</Configuration>

this throws Caused by: java.lang.ClassNotFoundException: com.lmax.disruptor.EventHandler but does not seem to be the same problem.
What exactly is what triggers the problem?

[jvz]

The trigger for this particular issue is that somewhere in LMAX, it uses sun.misc.Unsafe without catching java.lang.NoClassDefFoundError at the call site where they load it. You need to add that dependency to the class path to reproduce this.

[ppkarwasz]

sun.misc.Unsafe was removed from LMAX Disruptor two years ago: LMAX-Exchange/disruptor@63f9abc

Version 4.0.0 should run without problems (once we add support for 4.x).