Artemis cluster throws ClassNotFoundException: org.hornetq.core.remoting.impl.netty.NettyConnectorFactory - activemq-artemis

Question

I prepared java application with embedded Artemis broker. It is single jar that contains all dependencies.
I use org.apache.activemq:artemis-server:2.10.1 and I start broker in following way:
new EmbeddedActiveMQ().setConfigResourcePath( config ).start();
where config is a URL to configuration file.
I use one config file for master and one config file for slave.
master:
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<configuration xmlns="urn:activemq" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:activemq /schema/artemis-server.xsd">
<core xmlns="urn:activemq:core">
<persistence-enabled>true</persistence-enabled>
<security-enabled>false</security-enabled>
<acceptors>
<acceptor name="netty-acceptor">tcp://127.0.0.1:61617</acceptor>
</acceptors>
<bindings-directory>artemis/bindings</bindings-directory>
<journal-directory>artemis/journal</journal-directory>
<address-settings>
<address-setting match="#">
<dead-letter-address>DLQ</dead-letter-address>
</address-setting>
</address-settings>
<addresses>
<address name="DLQ">
<anycast>
<queue name="DLQ"/>
</anycast>
</address>
</addresses>
<connectors>
<!-- Connector used to be announced through cluster connections and notifications -->
<connector name="artemis">tcp://127.0.0.1:61617</connector>
</connectors>
<cluster-user>artemis-cluster</cluster-user>
<cluster-password>artemis-cluster</cluster-password>
<broadcast-groups>
<broadcast-group name="bg-group1">
<group-address>231.7.7.7</group-address>
<group-port>9876</group-port>
<broadcast-period>5000</broadcast-period>
<connector-ref>artemis</connector-ref>
</broadcast-group>
</broadcast-groups>
<discovery-groups>
<discovery-group name="dg-group1">
<group-address>231.7.7.7</group-address>
<group-port>9876</group-port>
<refresh-timeout>10000</refresh-timeout>
</discovery-group>
</discovery-groups>
<cluster-connections>
<cluster-connection name="my-cluster">
<address></address>
<connector-ref>artemis</connector-ref>
<message-load-balancing>ON_DEMAND</message-load-balancing>
<max-hops>1</max-hops>
<discovery-group-ref discovery-group-name="dg-group1"/>
</cluster-connection>
</cluster-connections>
<ha-policy>
<replication>
<master/>
</replication>
</ha-policy>
</core>
</configuration>
Slave:
<core xmlns="urn:activemq:core">
<persistence-enabled>true</persistence-enabled>
<security-enabled>false</security-enabled>
<acceptors>
<acceptor name="netty-acceptor">tcp://127.0.0.1:61618</acceptor>
</acceptors>
<bindings-directory>artemis/bindings</bindings-directory>
<journal-directory>artemis/journal</journal-directory>
<address-settings>
<address-setting match="#">
<dead-letter-address>DLQ</dead-letter-address>
</address-setting>
</address-settings>
<addresses>
<address name="DLQ">
<anycast>
<queue name="DLQ"/>
</anycast>
</address>
</addresses>
<connectors>
<!-- Connector used to be announced through cluster connections and notifications -->
<connector name="artemis">tcp://127.0.0.1:61618</connector>
</connectors>
<cluster-user>artemis-cluster</cluster-user>
<cluster-password>artemis-cluster</cluster-password>
<broadcast-groups>
<broadcast-group name="bg-group1">
<group-address>231.7.7.7</group-address>
<group-port>9876</group-port>
<broadcast-period>5000</broadcast-period>
<connector-ref>artemis</connector-ref>
</broadcast-group>
</broadcast-groups>
<discovery-groups>
<discovery-group name="dg-group1">
<group-address>231.7.7.7</group-address>
<group-port>9876</group-port>
<refresh-timeout>10000</refresh-timeout>
</discovery-group>
</discovery-groups>
<cluster-connections>
<cluster-connection name="my-cluster">
<address></address>
<connector-ref>artemis</connector-ref>
<message-load-balancing>ON_DEMAND</message-load-balancing>
<max-hops>1</max-hops>
<discovery-group-ref discovery-group-name="dg-group1"/>
</cluster-connection>
</cluster-connections>
<ha-policy>
<replication>
<slave/>
</replication>
</ha-policy>
</core>
It works properly on Windows 10 and Centos 7. It does not work on Oracle Linux 7. All machines use the same Java version.
java -version
openjdk version "11.0.9" 2020-10-20
OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.9+11)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.9+11, mixed mode)
There is no any exception on Windows and Centos and I see following logs:
11:14:30.867 [Thread-0] INFO org.apache.activemq.artemis.core.server - AMQ221025: Replication: sending NIOSequentialFile...
and
11:14:33.911 [Thread-1 (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$6#2a3c96e3)] INFO org.apache.activemq.artemis.core.server - AMQ221031: backup announced
Exactly the same jar and exaclty the same configuration file throws exception on Oracle Linux:
11:31:56.074 [Thread-0 (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$6#63b1d4fa)] WARN org.apache.activemq.artemis.core.client - AMQ212025: did not connect the cluster connection to other nodes
java.lang.IllegalStateException: java.lang.ClassNotFoundException: org.hornetq.core.remoting.impl.netty.NettyConnectorFactory
at org.apache.activemq.artemis.utils.ClassloadingUtil.newInstanceFromClassLoader(ClassloadingUtil.java:59) ~[broker.jar:?]
at org.apache.activemq.artemis.core.client.impl.ClientSessionFactoryImpl$2.run(ClientSessionFactoryImpl.java:996) ~[broker.jar:?]
at org.apache.activemq.artemis.core.client.impl.ClientSessionFactoryImpl$2.run(ClientSessionFactoryImpl.java:993) ~[broker.jar:?]
at java.security.AccessController.doPrivileged(Native Method) ~[?:?]
at org.apache.activemq.artemis.core.client.impl.ClientSessionFactoryImpl.instantiateConnectorFactory(ClientSessionFactoryImpl.java:993) ~[broker.jar:?]
at org.apache.activemq.artemis.core.client.impl.ClientSessionFactoryImpl.<init>(ClientSessionFactoryImpl.java:181) ~[broker.jar:?]
at org.apache.activemq.artemis.core.client.impl.ServerLocatorImpl.createSessionFactory(ServerLocatorImpl.java:798) ~[broker.jar:?]
at org.apache.activemq.artemis.core.client.impl.ServerLocatorImpl.connect(ServerLocatorImpl.java:655) ~[broker.jar:?]
at org.apache.activemq.artemis.core.client.impl.ServerLocatorImpl.connect(ServerLocatorImpl.java:637) ~[broker.jar:?]
at org.apache.activemq.artemis.core.client.impl.ServerLocatorImpl$4.run(ServerLocatorImpl.java:595) ~[broker.jar:?]
at org.apache.activemq.artemis.utils.actors.OrderedExecutor.doTask(OrderedExecutor.java:42) ~[broker.jar:?]
at org.apache.activemq.artemis.utils.actors.OrderedExecutor.doTask(OrderedExecutor.java:31) ~[broker.jar:?]
at org.apache.activemq.artemis.utils.actors.ProcessorBase.executePendingTasks(ProcessorBase.java:66) ~[broker.jar:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
at org.apache.activemq.artemis.utils.ActiveMQThreadFactory$1.run(ActiveMQThreadFactory.java:118) [broker.jar:?]
Caused by: java.lang.ClassNotFoundException: org.hornetq.core.remoting.impl.netty.NettyConnectorFactory
at jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581) ~[?:?]
at jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[?:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:522) ~[?:?]
at org.apache.activemq.artemis.utils.ClassloadingUtil.newInstanceFromClassLoader(ClassloadingUtil.java:55) ~[broker.jar:?]
... 15 more
Master and slave both throw the same exception. Why Artemis wants to use org.hornetq.core.remoting.impl.netty.NettyConnectorFactory on Oracle Linux? I debugged my application on Windows and org.apache.activemq.artemis.core.remoting.impl.netty.NettyConnectorFactory is used there. Where it can be configured? Maybe there is some configuration file in user directory or sth like that? Probably I can solve the issue by adding hornetq to dependencies but I prefer to use NettyConnectorFactory from Artemis. I do not understand why one machine uses different NettyConnectorFactory than the other two machines.

Answer 1

This is almost certainly being caused by a HornetQ broker on your network which is using the same group-address and group-port (i.e. 231.7.7.7:9876) to broadcast its connector information. You're using the default values so this isn't terribly surprising. You should either find this HornetQ broker and stop it or change your Artemis' cluster configuration to use a different group-address and/or group-port.