JDK 11 causes NoClassDefFoundError | AEM 6.5

Last updated on 27 Des 2022

JDK 11 causes NoClassDefFoundError AEM 6.5

Issue

The error below is observed in the logs after upgrading to Java 11 with AEM 6.5.x.

15.09.2020 00:30:20.868 *ERROR* [FelixStartLevel] org.apache.sling.scripting.sightly bundle org.apache.sling.scripting.sightly:1.1.2.1_4_0 (557)[org.apache.sling.scripting.sightly.impl.engine.extension.use.JavaUseProvider(3410)] :  Error during instantiation of the implementation object (java.lang.NoClassDefFoundError: jdk/internal/reflect/ConstructorAccessorImpl) 
java.lang.NoClassDefFoundError: jdk/internal/reflect/ConstructorAccessorImpl 
 at java.base/jdk.internal.misc.Unsafe.defineClass0(Native Method) 
 at java.base/jdk.internal.misc.Unsafe.defineClass(Unsafe.java:1192) 
 at java.base/jdk.internal.reflect.ClassDefiner.defineClass(ClassDefiner.java:63) 
 at java.base/jdk.internal.reflect.MethodAccessorGenerator$1.run(MethodAccessorGenerator.java:400) 
 at java.base/jdk.internal.reflect.MethodAccessorGenerator$1.run(MethodAccessorGenerator.java:394) 
 at java.base/java.security.AccessController.doPrivileged(Native Method) 
... 
Caused by: java.lang.ClassNotFoundException: Unable to load class 'jdk.internal.reflect.ConstructorAccessorImpl' 
 at org.apache.felix.framework.BundleWiringImpl$1.loadClass(BundleWiringImpl.java:91) 
 at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) 
 at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1463) 
 at org.apache.felix.framework.BundleWiringImpl.access$300(BundleWiringImpl.java:79) 
 at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:1982) 
 at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) 
 ... 111 common frames omitted

Solution

This issue is due to the fact that CXF packages have been removed from AEM and you have to install those externally.

Stop AEM
Find and open this file in a text editor: crx-quickstart/conf/sling.properties
Modify this line:

Before:

org.osgi.framework.bootdelegation=com.yourkit.*, ${org.apache.sling.launcher.bootdelegation}

After:

org.osgi.framework.bootdelegation=sun.*,com.sun.*,jdk.internal.reflect,jdk.internal.reflect.*,com.yourkit.*,${org.apache.sling.launcher.bootdelegation}

4. Start AEM

Note:

See here for technical details on this issue.