fix(jmx): avoid NPE in ConnectionView.getWireFormatInfo

activemq-broker/src/main/java/org/apache/activemq/broker/jmx/ConnectionView.java

@@ -23,6 +23,7 @@
 
 import org.apache.activemq.broker.Connection;
 import org.apache.activemq.broker.TransportConnection;
+import org.apache.activemq.command.WireFormatInfo;
 import org.apache.activemq.util.IOExceptionSupport;
 
 public class ConnectionView implements ConnectionViewMBean {
@@ -201,8 +202,9 @@ public long getConnectedTimestamp() {
 
     @Override
     public String getWireFormatInfo() {
-        if(connection instanceof TransportConnection) {
-            return ((TransportConnection)connection).getRemoteWireFormatInfo().toString();
+        if (connection instanceof TransportConnection) {
+            WireFormatInfo info = ((TransportConnection) connection).getRemoteWireFormatInfo();
+            return (info != null) ? info.toString() : "WireFormatInfo not available";
         }
         return "WireFormatInfo not available";
     }

activemq-broker/src/test/java/org/apache/activemq/broker/jmx/ConnectionViewTest.java

@@ -0,0 +1,104 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.activemq.broker.jmx;
+
+import org.apache.activemq.ActiveMQConnectionFactory;
+import org.apache.activemq.broker.BrokerService;
+import org.apache.activemq.broker.TransportConnection;
+import org.apache.activemq.broker.TransportConnector;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import jakarta.jms.Connection;
+import java.lang.reflect.Field;
+import java.net.URI;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+
+/**
+ * Regression tests for ConnectionView JMX attribute accessors.
+ */
+public class ConnectionViewTest {
+
+    private BrokerService broker;
+    private URI brokerConnectURI;
+
+    @Before
+    public void startBroker() throws Exception {
+        broker = new BrokerService();
+        broker.setPersistent(false);
+
+        TransportConnector connector = broker.addConnector(new TransportConnector());
+        connector.setUri(new URI("tcp://0.0.0.0:0"));
+        connector.setName("tcp");
+
+        broker.start();
+        broker.waitUntilStarted();
+
+        brokerConnectURI = broker.getConnectorByName("tcp").getConnectUri();
+    }
+
+    @After
+    public void stopBroker() throws Exception {
+        if (broker != null) {
+            broker.stop();
+            broker.waitUntilStopped();
+        }
+    }
+
+    @Test
+    public void testGetWireFormatInfoWhenPresent() throws Exception {
+        Connection connection = new ActiveMQConnectionFactory(brokerConnectURI).createConnection();
+        connection.start();
+        try {
+            ConnectionView view = new ConnectionView(getTransportConnection());
+            String info = view.getWireFormatInfo();
+            assertNotNull(info);
+            assertFalse("WireFormatInfo not available".equals(info));
+        } finally {
+            connection.stop();
+        }
+    }
+
+    @Test
+    public void testGetWireFormatInfoWhenRemoteInfoNull() throws Exception {
+        Connection connection = new ActiveMQConnectionFactory(brokerConnectURI).createConnection();
+        connection.start();
+        try {
+            TransportConnection transportConnection = getTransportConnection();
+            Field field = TransportConnection.class.getDeclaredField("wireFormatInfo");
+            field.setAccessible(true);
+            field.set(transportConnection, null);
+
+            ConnectionView view = new ConnectionView(transportConnection);
+            assertEquals("WireFormatInfo not available", view.getWireFormatInfo());
+        } finally {
+            connection.stop();
+        }
+    }
+
+    private TransportConnection getTransportConnection() {
+        CopyOnWriteArrayList<TransportConnection> connections =
+                broker.getConnectorByName("tcp").getConnections();
+        assertEquals(1, connections.size());
+        return connections.get(0);
+    }
+}