With consumer using openwire, a stomp producer send a 100KB message, then the broker throughs the error:

Error during message dispatch: java.lang.NullPointerException
at org.apache.activemq.artemis.core.message.impl.CoreMessage.encode(CoreMessage.java:533) [artemis-core-client-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.core.message.impl.CoreMessage.checkEncode(CoreMessage.java:219) [artemis-core-client-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.core.message.impl.CoreMessage.getReadOnlyBodyBuffer(CoreMessage.java:196) [artemis-core-client-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.core.protocol.openwire.OpenWireMessageConverter.toAMQMessage(OpenWireMessageConverter.java:486) [artemis-openwire-protocol-2.0.0.amq-700005-redhat-1.jar:]
at org.apache.activemq.artemis.core.protocol.openwire.OpenWireMessageConverter.createMessageDispatch(OpenWireMessageConverter.java:427) [artemis-openwire-protocol-2.0.0.amq-700005-redhat-1.jar:]
at org.apache.activemq.artemis.core.protocol.openwire.amq.AMQConsumer.handleDeliver(AMQConsumer.java:224) [artemis-openwire-protocol-2.0.0.amq-700005-redhat-1.jar:]
at org.apache.activemq.artemis.core.protocol.openwire.amq.AMQSession.sendMessage(AMQSession.java:243) [artemis-openwire-protocol-2.0.0.amq-700005-redhat-1.jar:]
at org.apache.activemq.artemis.core.server.impl.ServerConsumerImpl.deliverStandardMessage(ServerConsumerImpl.java:1050) [artemis-server-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.core.server.impl.ServerConsumerImpl.proceedDeliver(ServerConsumerImpl.java:430) [artemis-server-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.core.server.impl.QueueImpl.proceedDeliver(QueueImpl.java:2649) [artemis-server-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.core.server.impl.QueueImpl.deliver(QueueImpl.java:2138) [artemis-server-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.core.server.impl.QueueImpl.access$1700(QueueImpl.java:102) [artemis-server-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.core.server.impl.QueueImpl$DeliverRunner.run(QueueImpl.java:2882) [artemis-server-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at org.apache.activemq.artemis.utils.OrderedExecutorFactory$OrderedExecutor$ExecutorTask.run(OrderedExecutorFactory.java:101) [artemis-commons-2.0.0.amq-700005-redhat-1.jar:2.0.0.amq-700005-redhat-1]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [rt.jar:1.8.0_141]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [rt.jar:1.8.0_141]
at java.lang.Thread.run(Thread.java:748) [rt.jar:1.8.0_141]

workaround is to set stomp-min-large-message-size larger than size of stomp message sent.