at ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTcpAppender #84

NehaK214 · 2022-10-07T05:27:42Z

NehaK214
Oct 7, 2022

While integrating GelfTcpAppender we are getting the below mentioned error:
ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTcpAppender

Stack Trace For the same:

ERROR in ch.qos.logback.core.joran.action.AppenderAction - Could not create an Appender of type [de.siegmar.logbackgelf.GelfTcpAppender]. ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTcpAppender
[INFO] at ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTcpAppender
[INFO] at at ch.qos.logback.core.util.OptionHelper.instantiateByClassNameAndParameter(Unknown Source)
[INFO] at at ch.qos.logback.core.util.OptionHelper.instantiateByClassName(Unknown Source)
[INFO] at at ch.qos.logback.core.util.OptionHelper.instantiateByClassName(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.action.AppenderAction.begin(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.spi.Interpreter.callBeginAction(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.spi.Interpreter.startElement(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.spi.Interpreter.startElement(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.spi.EventPlayer.play(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(Unknown Source)
[INFO] at at com.hivemq.bootstrap.LoggingBootstrap.overrideLogbackXml(Unknown Source)
[INFO] at at com.hivemq.bootstrap.LoggingBootstrap.initLogging(Unknown Source)
[INFO] at at com.hivemq.HiveMQServer.a(Unknown Source)
[INFO] at at com.hivemq.HiveMQServer.d(Unknown Source)
[INFO] at at com.hivemq.HiveMQServer.main(Unknown Source)
[INFO] Caused by: java.lang.ClassNotFoundException: de.siegmar.logbackgelf.GelfTcpAppender
[INFO] at at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
[INFO] at at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
[INFO] at at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
[INFO] at ... 17 common frames omitted
[INFO] 10:51:37,612 |-ERROR in ch.qos.logback.core.joran.spi.Interpreter@9:86 - ActionException in Action for tag [appender] ch.qos.logback.core.joran.spi.ActionException: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTcpAppender
[INFO] at ch.qos.logback.core.joran.spi.ActionException: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTcpAppender
[INFO] at at ch.qos.logback.core.joran.action.AppenderAction.begin(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.spi.Interpreter.callBeginAction(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.spi.Interpreter.startElement(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.spi.Interpreter.startElement(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.spi.EventPlayer.play(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(Unknown Source)
[INFO] at at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(Unknown Source)
[INFO] at at com.hivemq.bootstrap.LoggingBootstrap.overrideLogbackXml(Unknown Source)
[INFO] at at com.hivemq.bootstrap.LoggingBootstrap.initLogging(Unknown Source)
[INFO] at at com.hivemq.HiveMQServer.a(Unknown Source)
[INFO] at at com.hivemq.HiveMQServer.d(Unknown Source)
[INFO] at at com.hivemq.HiveMQServer.main(Unknown Source)
[INFO] Caused by: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTcpAppender
[INFO] at at ch.qos.logback.core.util.OptionHelper.instantiateByClassNameAndParameter(Unknown Source)
[INFO] at at ch.qos.logback.core.util.OptionHelper.instantiateByClassName(Unknown Source)
[INFO] at at ch.qos.logback.core.util.OptionHelper.instantiateByClassName(Unknown Source)
[INFO] at ... 14 common frames omitted
[INFO] Caused by: java.lang.ClassNotFoundException: de.siegmar.logbackgelf.GelfTcpAppender
[INFO] at at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
[INFO] at at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
[INFO] at at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
[INFO] at ... 17 common frames omitted

Logback.xml Code:

%-30(%d %level)- %msg%n%ex

            <appender name="GELF" class="de.siegmar.logbackgelf.GelfTcpAppender">
                            <graylogHost>127.0.0.1</graylogHost>
                            <graylogPort>12201</graylogPort>
            </appender>
            <appender name="ASYNC-GELF" class="ch.qos.logback.classic.AsyncAppender">
                            <neverBlock>true</neverBlock>
                            <appender-ref ref="GELF" />
            </appender>
            <root level="${LOG_LEVEL:-INFO}">
                            <appender-ref ref="${LOG_APPENDER:-CONSOLE}" />
            </root>

Dependencies Used in pom.xml:

de.siegmar logback-gelf 2.0.0

Java Version Used: 11

Answered by osiegmar

Oct 7, 2022

The root cause of your stacktrace says "Caused by: java.lang.ClassNotFoundException: de.siegmar.logbackgelf.GelfTcpAppender".

So it seems that the logback-gelf library is missing from your runtime classpath as that class is clearly part of the library.

View full answer

NehaK214 · 2022-10-07T05:31:59Z

NehaK214
Oct 7, 2022
Author

FYI we have also tried updating logback-gelf version to 4.0.2 however we are getting the same issue

0 replies

osiegmar · 2022-10-07T06:12:31Z

osiegmar
Oct 7, 2022
Maintainer

The root cause of your stacktrace says "Caused by: java.lang.ClassNotFoundException: de.siegmar.logbackgelf.GelfTcpAppender".

So it seems that the logback-gelf library is missing from your runtime classpath as that class is clearly part of the library.

1 reply

chinavolcano Jan 12, 2026

Hello @osiegmar,
This issue exists even in a simple Spring Boot application, and it's not due to missing libraries.
The main reason【Caused by: [CIRCULAR REFERENCE: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTCPAppender]】

You can test with the following package

xzt-test-ad.zip

【The exception list 】
ERROR in ch.qos.logback.core.model.processor.AppenderModelHandler - Could not create an Appender of type [de.siegmar.logbackgelf.GelfTCPAppender]. ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTCPAppender
ERROR in ch.qos.logback.core.model.processor.DefaultProcessor@17d88132 - Failed to traverse model appender ch.qos.logback.core.model.processor.ModelHandlerException: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTCPAppender
at org.springframework.boot.logging.logback.LogbackLoggingSystem.reportConfigurationErrorsIfNecessary(LogbackLoggingSystem.java:296)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.loadConfiguration(LogbackLoggingSystem.java:274)
at org.springframework.boot.logging.AbstractLoggingSystem.initializeWithConventions(AbstractLoggingSystem.java:86)
at org.springframework.boot.logging.AbstractLoggingSystem.initialize(AbstractLoggingSystem.java:65)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.initialize(LogbackLoggingSystem.java:197)
at org.springframework.boot.context.logging.LoggingApplicationListener.initializeSystem(LoggingApplicationListener.java:337)
... 19 more
Suppressed: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTCPAppender
at ch.qos.logback.core.util.OptionHelper.instantiateByClassNameAndParameter(OptionHelper.java:69)
at ch.qos.logback.core.util.OptionHelper.instantiateByClassName(OptionHelper.java:44)
at ch.qos.logback.core.util.OptionHelper.instantiateByClassName(OptionHelper.java:33)
at ch.qos.logback.core.model.processor.AppenderModelHandler.handle(AppenderModelHandler.java:67)
at ch.qos.logback.core.model.processor.DefaultProcessor.secondPhaseTraverse(DefaultProcessor.java:241)
at ch.qos.logback.core.model.processor.DefaultProcessor.secondPhaseTraverse(DefaultProcessor.java:253)
at ch.qos.logback.core.model.processor.DefaultProcessor.traversalLoop(DefaultProcessor.java:90)
at ch.qos.logback.core.model.processor.DefaultProcessor.process(DefaultProcessor.java:106)
at ch.qos.logback.core.joran.GenericXMLConfigurator.processModel(GenericXMLConfigurator.java:222)
at org.springframework.boot.logging.logback.SpringBootJoranConfigurator.processModel(SpringBootJoranConfigurator.java:139)
at ch.qos.logback.core.joran.GenericXMLConfigurator.doConfigure(GenericXMLConfigurator.java:178)
at ch.qos.logback.core.joran.GenericXMLConfigurator.doConfigure(GenericXMLConfigurator.java:123)
at ch.qos.logback.core.joran.GenericXMLConfigurator.doConfigure(GenericXMLConfigurator.java:66)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.configureByResourceUrl(LogbackLoggingSystem.java:305)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.lambda$loadConfiguration$0(LogbackLoggingSystem.java:267)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.withLoggingSuppressed(LogbackLoggingSystem.java:491)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.loadConfiguration(LogbackLoggingSystem.java:257)
... 23 more
Caused by: java.lang.ClassNotFoundException: de.siegmar.logbackgelf.GelfTCPAppender
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
at ch.qos.logback.core.util.OptionHelper.instantiateByClassNameAndParameter(OptionHelper.java:56)
... 39 more
Suppressed: ch.qos.logback.core.model.processor.ModelHandlerException: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTCPAppender
at ch.qos.logback.core.model.processor.AppenderModelHandler.handle(AppenderModelHandler.java:75)
at ch.qos.logback.core.model.processor.DefaultProcessor.secondPhaseTraverse(DefaultProcessor.java:241)
at ch.qos.logback.core.model.processor.DefaultProcessor.secondPhaseTraverse(DefaultProcessor.java:253)
at ch.qos.logback.core.model.processor.DefaultProcessor.traversalLoop(DefaultProcessor.java:90)
at ch.qos.logback.core.model.processor.DefaultProcessor.process(DefaultProcessor.java:106)
at ch.qos.logback.core.joran.GenericXMLConfigurator.processModel(GenericXMLConfigurator.java:222)
at org.springframework.boot.logging.logback.SpringBootJoranConfigurator.processModel(SpringBootJoranConfigurator.java:139)
at ch.qos.logback.core.joran.GenericXMLConfigurator.doConfigure(GenericXMLConfigurator.java:178)
at ch.qos.logback.core.joran.GenericXMLConfigurator.doConfigure(GenericXMLConfigurator.java:123)
at ch.qos.logback.core.joran.GenericXMLConfigurator.doConfigure(GenericXMLConfigurator.java:66)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.configureByResourceUrl(LogbackLoggingSystem.java:305)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.lambda$loadConfiguration$0(LogbackLoggingSystem.java:267)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.withLoggingSuppressed(LogbackLoggingSystem.java:491)
at org.springframework.boot.logging.logback.LogbackLoggingSystem.loadConfiguration(LogbackLoggingSystem.java:257)
... 23 more
Caused by: [CIRCULAR REFERENCE: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type de.siegmar.logbackgelf.GelfTCPAppender]

osiegmar · 2026-01-12T07:20:11Z

osiegmar
Jan 12, 2026
Maintainer

@chinavolcano Please provide a link to a public GitHub repository that demonstrates the problem. For security reasons I do not download/open ZIP files.

0 replies

chinavolcano · 2026-01-12T09:04:15Z

chinavolcano
Jan 12, 2026

Thanks,
Pls look over the codebase below.

https://github.com/chinavolcano/xzt-test-logback-gelf/tree/main

I suspect the issue stems from third-party appenders with logback's compatibility .
For example: I modified logback.xml's class="de.siegmar.logbackgelf.GelfUDPAppender' to class="Hello", but the issue persists.

2 replies

chinavolcano Jan 12, 2026

@osiegmar

osiegmar Jan 24, 2026
Maintainer

I just tried, but repository does not seem to exist (anymore).

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Oct 7, 2022
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osiegmar
Oct 7, 2022
Maintainer

osiegmar
Jan 12, 2026
Maintainer

chinavolcano
Jan 12, 2026

osiegmar Jan 24, 2026
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