https://issues.apache.org/jira/browse/AMQ-4820 - find elements by ns and local name to deal with namespace prefix. Ensure we trap all errors on plugin start so we don't cause a failed broker start, and trap no broker element with a better error

activemq-runtime-config/src/main/java/org/apache/activemq/plugin/RuntimeConfigurationBroker.java

@@ -657,16 +657,22 @@ public class RuntimeConfigurationBroker extends BrokerFilter {
                 dbf.setNamespaceAware(true);
                 DocumentBuilder db = dbf.newDocumentBuilder();
                 Document doc = db.parse(configToMonitor.getInputStream());
-                Node brokerRootNode = doc.getElementsByTagName("broker").item(0);
+                Node brokerRootNode = doc.getElementsByTagNameNS("*","broker").item(0);
 
-                JAXBElement<DtoBroker> brokerJAXBElement =
+                if (brokerRootNode != null) {
-                        unMarshaller.unmarshal(brokerRootNode, DtoBroker.class);
-                jaxbConfig = brokerJAXBElement.getValue();
 
-                // if we can parse we can track mods
+                    JAXBElement<DtoBroker> brokerJAXBElement =
-                lastModified = configToMonitor.lastModified();
+                            unMarshaller.unmarshal(brokerRootNode, DtoBroker.class);
+                    jaxbConfig = brokerJAXBElement.getValue();
 
-                loadPropertiesPlaceHolderSupport(doc);
+                    // if we can parse we can track mods
+                    lastModified = configToMonitor.lastModified();
+
+                    loadPropertiesPlaceHolderSupport(doc);
+
+                } else {
+                    info("Failed to find 'broker' element by tag in: " + configToMonitor);
+                }
 
             } catch (IOException e) {
                 info("Failed to access: " + configToMonitor, e);
@@ -676,6 +682,8 @@ public class RuntimeConfigurationBroker extends BrokerFilter {
                 info("Failed to document parse: " + configToMonitor, e);
             } catch (SAXException e) {
                 info("Failed to find broker element in: " + configToMonitor, e);
+            } catch (Exception e) {
+                info("Unexpected exception during load of: " + configToMonitor, e);
             }
         }
         return jaxbConfig;

activemq-runtime-config/src/test/java/org/apache/activemq/CustomPropertiesBean.java

@@ -0,0 +1,37 @@
+/**
+ * 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;
+
+import java.util.Properties;
+import org.springframework.beans.factory.FactoryBean;
+
+public class CustomPropertiesBean implements FactoryBean<Properties> {
+    @Override
+    public Properties getObject() throws Exception {
+        return System.getProperties();
+    }
+
+    @Override
+    public Class<?> getObjectType() {
+        return Properties.class;
+    }
+
+    @Override
+    public boolean isSingleton() {
+        return false;
+    }
+}

activemq-runtime-config/src/test/java/org/apache/activemq/NameSpaceXmlLoadTest.java

@@ -0,0 +1,58 @@
+/**
+ * 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;
+
+import java.util.HashMap;
+import javax.management.ObjectName;
+import org.apache.activemq.plugin.RuntimeConfigurationBroker;
+import org.apache.activemq.plugin.jmx.RuntimeConfigurationViewMBean;
+import org.apache.activemq.util.IOHelper;
+import org.apache.activemq.util.IntrospectionSupport;
+import org.junit.Test;
+
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
+public class NameSpaceXmlLoadTest extends RuntimeConfigTestSupport {
+
+    @Test
+    public void testCanLoad() throws Exception {
+        final String brokerConfig =  "namespace-prefix";
+        System.setProperty("data", IOHelper.getDefaultDataDirectory());
+        System.setProperty("broker-name", brokerConfig);
+        startBroker(brokerConfig);
+        assertTrue("broker alive", brokerService.isStarted());
+        assertEquals("nameMatch", brokerConfig, brokerService.getBrokerName());
+
+        // verify runtimeConfig active
+        ObjectName objectName =
+                new ObjectName(brokerService.getBrokerObjectName().toString() +
+                        RuntimeConfigurationBroker.objectNamePropsAppendage);
+        RuntimeConfigurationViewMBean runtimeConfigurationView =
+                (RuntimeConfigurationViewMBean) brokerService.getManagementContext().newProxyInstance(objectName,
+                        RuntimeConfigurationViewMBean.class, false);
+
+        HashMap<String, String> props = new HashMap<String, String>();
+        IntrospectionSupport.getProperties(runtimeConfigurationView, props, null);
+        LOG.info("mbean attributes before: " + props);
+        String propOfInterest = "modified";
+        assertNotEquals("modified is valid", "unknown", props.get(propOfInterest));
+
+    }
+}

activemq-runtime-config/src/test/resources/org/apache/activemq/namespace-prefix.xml

@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+    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.
+-->
+<tag0:beans xmlns:tag0="http://www.springframework.org/schema/beans"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/activemq-core.xsd">
+  <tag0:bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
+    <tag0:property name="properties">
+      <tag0:bean class="org.apache.activemq.CustomPropertiesBean"/>
+    </tag0:property>
+  </tag0:bean>
+  <amq:broker xmlns:amq="http://activemq.apache.org/schema/core" start="false" dataDirectory="${data}" persistent="false"
+              brokerName="${broker-name}">
+    <amq:destinationPolicy>
+      <amq:policyMap>
+        <amq:policyEntries>
+          <amq:policyEntry topic=">" producerFlowControl="true">
+            <amq:pendingMessageLimitStrategy>
+              <amq:constantPendingMessageLimitStrategy limit="1000"/>
+            </amq:pendingMessageLimitStrategy>
+          </amq:policyEntry>
+          <amq:policyEntry queue=">" producerFlowControl="true" memoryLimit="1mb"/>
+        </amq:policyEntries>
+      </amq:policyMap>
+    </amq:destinationPolicy>
+    <amq:managementContext>
+      <amq:managementContext createConnector="false"/>
+    </amq:managementContext>
+    <amq:plugins>
+      <amq:jaasAuthenticationPlugin configuration="karaf"/>
+      <amq:runtimeConfigurationPlugin checkPeriod="1000"/>
+    </amq:plugins>
+    <amq:systemUsage>
+      <amq:systemUsage>
+        <amq:memoryUsage>
+          <amq:memoryUsage limit="64 mb"/>
+        </amq:memoryUsage>
+        <amq:storeUsage>
+          <amq:storeUsage limit="100 gb"/>
+        </amq:storeUsage>
+        <amq:tempUsage>
+          <amq:tempUsage limit="50 gb"/>
+        </amq:tempUsage>
+      </amq:systemUsage>
+    </amq:systemUsage>
+    <amq:transportConnectors>
+      <amq:transportConnector name="openwire" uri="tcp://0.0.0.0:0?maximumConnections=1000"/>
+    </amq:transportConnectors>
+  </amq:broker>
+</tag0:beans>