[LOG4J2-2463] ClassNotFoundException when log4j2 is used with slf4j on module path in java 11

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Workaround
• Affects Version/s: 2.11.0
• Labels: 3.0
• Assignee: Ralph Goers
• Reporter: Pavel_K
• Created: 02/Oct/18 19:40
• Updated: 23/Nov/21 06:49
• Resolved: 23/Nov/21 06:49

Description

In order to use log4j2 with slf4j I use the following jars on my module path:

    slf4j-api-1.7.25.jar
    log4j-slf4j-impl-2.11.0.jar
    log4j-core-2.11.0.jar
    log4j-api-2.11.0.jar

However, I get

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/logging/log4j/spi/AbstractLoggerAdapter
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1095)
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:206)
	at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:760)
	at java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:681)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:606)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:580)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	at org.apache.logging.log4j.slf4j.impl@2.11.0/org.slf4j.impl.StaticLoggerBinder.<clinit>(StaticLoggerBinder.java:36)
	at slf4j.api@1.7.25/org.slf4j.LoggerFactory.bind(LoggerFactory.java:150)
	at slf4j.api@1.7.25/org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:124)
	at slf4j.api@1.7.25/org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:412)
	at slf4j.api@1.7.25/org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:357)
	at slf4j.api@1.7.25/org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:383)
	at com.noname.alpha.core/com.noname.alpha.core.internal.Launcher.<clinit>(Launcher.java:38)
Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.spi.AbstractLoggerAdapter
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:582)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	... 17 more

The problem is solved when I delete log4j-api-2.11.0.jar/META-INF/versions/9/module-info.class file