WildFly v36.0.0.Final, Java 21, RedHat OS v9.

standalone-full-ha profile

Specify system property: brokerconfig.maxDiskUsage=-1

During startup, WildFly gives error:

2025-05-05 08:02:41,217 ERROR [org.apache.activemq.artemis.core.server] (ServerService Thread Pool – 73) AMQ224097: Failed to start server: java.lang.NoClassDefFoundError: org/xml/sax/SAXException
        at org.apache.activemq.artemis@2.40.0//org.apache.activemq.artemis.core.config.impl.ConfigurationImpl.parsePrefixedProperties(ConfigurationImpl.java:640)
        at org.apache.activemq.artemis@2.40.0//org.apache.activemq.artemis.core.config.impl.ConfigurationImpl.parsePrefixedProperties(ConfigurationImpl.java:614)
        at org.apache.activemq.artemis@2.40.0//org.apache.activemq.artemis.core.config.impl.ConfigurationImpl.parseProperties(ConfigurationImpl.java:595)
        at org.apache.activemq.artemis@2.40.0//org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl.internalStart(ActiveMQServerImpl.java:683)
        at org.apache.activemq.artemis@2.40.0//org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl.start(ActiveMQServerImpl.java:633)
        at org.apache.activemq.artemis@2.40.0//org.apache.activemq.artemis.jms.server.impl.JMSServerManagerImpl.start(JMSServerManagerImpl.java:354)
        at org.wildfly.extension.messaging-activemq//org.wildfly.extension.messaging.activemq.jms.JMSService.doStart(JMSService.java:194)
        at org.wildfly.extension.messaging-activemq//org.wildfly.extension.messaging.activemq.jms.JMSService$1.run(JMSService.java:84)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
        at org.jboss.threads@2.4.0.Final//org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
        at org.jboss.threads@2.4.0.Final//org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1990)
        at org.jboss.threads@2.4.0.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
        at org.jboss.threads@2.4.0.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1348)
        at java.base/java.lang.Thread.run(Thread.java:1583)
        at org.jboss.threads@2.4.0.Final//org.jboss.threads.JBossThread.run(JBossThread.java:513)
Caused by: java.lang.ClassNotFoundException: org.xml.sax.SAXException from [Module "org.apache.activemq.artemis.client" version 2.40.0 from local module loader @482d776b (finder: local module finder @4052274f (roots: /opt/jboss-eap/modules,/opt/jboss-eap/modules/system/layers/base,/opt/xpe/var/eap/modules))]
        at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:201)
        at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:408)
        at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:396)
        at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:115)
        ... 16 more

Analysis:

ConfigurationImpl.parsePrefixedProperties(ConfigurationImpl.java:640):

            value = XMLUtil.replaceSystemPropsInString(value);

Class XMLUtils contains:

            import org.xml.sax.SAXException;

This import is provided by "java.xml" Java21 module. It seems this module is not available on module "org.apache.activemq.artemis.client" module path.