log4j using by the agent will attempt to loading the application's log4j2 class, leads to ClassNotFoundException

the log here

ERROR StatusLogger Unable to create custom ContextSelector. Falling back to default.
 java.lang.ClassNotFoundException: org/apache/logging/log4j/core/async/AsyncLoggerContextSelector
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:264)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.util.LoaderUtil.loadClass(LoaderUtil.java:168)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.util.LoaderUtil.newInstanceOf(LoaderUtil.java:207)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.util.LoaderUtil.newCheckedInstanceOf(LoaderUtil.java:228)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.util.LoaderUtil.newCheckedInstanceOfProperty(LoaderUtil.java:253)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.util.Loader.newCheckedInstanceOfProperty(Loader.java:338)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.impl.Log4jContextFactory.createContextSelector(Log4jContextFactory.java:98)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.impl.Log4jContextFactory.<init>(Log4jContextFactory.java:59)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at java.lang.Class.newInstance(Class.java:442)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.LogManager.<clinit>(LogManager.java:94)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.spi.ThreadContextMapFactory.createThreadContextMap(ThreadContextMapFactory.java:99)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.ThreadContext.init(ThreadContext.java:225)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.ThreadContext.<clinit>(ThreadContext.java:203)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.impl.ContextDataInjectorFactory.createDefaultInjector(ContextDataInjectorFactory.java:83)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.impl.ContextDataInjectorFactory.createInjector(ContextDataInjectorFactory.java:67)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.lookup.ContextMapLookup.<init>(ContextMapLookup.java:34)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.lookup.Interpolator.<init>(Interpolator.java:120)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.lookup.Interpolator.<init>(Interpolator.java:87)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.config.ConfigurationFactory.<init>(ConfigurationFactory.java:133)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.config.ConfigurationFactory$Factory.<init>(ConfigurationFactory.java:354)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.config.ConfigurationFactory$Factory.<init>(ConfigurationFactory.java:354)
	at co.elastic.apm.agent.shaded.apache.logging.log4j.core.config.ConfigurationFactory.<clinit>(ConfigurationFactory.java:131)
	at co.elastic.apm.agent.logging.LoggingConfiguration.init(LoggingConfiguration.java:198)
	at co.elastic.apm.agent.impl.ElasticApmTracerBuilder.<init>(ElasticApmTracerBuilder.java:92)
	at co.elastic.apm.agent.bci.ElasticApmAgent.initialize(ElasticApmAgent.java:127)
	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 co.elastic.apm.agent.bci.AgentMain.init(AgentMain.java:100)
	at co.elastic.apm.agent.bci.AgentMain.premain(AgentMain.java:54)
	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 sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:386)
	at sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:401)

[CoderLan0668]

Thanks for reporting! Which agent version are you using? This error seems to be handled by using a default context selector instead. Besides this log message, is there anything not working as expected?

the agent not working, No Class has been retransformed. the agent was built from master branch, lastest comit is 518afc790674f311b00fb188fe2444b1a6a81a6a

[CoderLan0668]

@eyalkoren The error logs has gone, and the agent work well.