I am running a client/server application using JBoss.
How can I connect to the server JVM's MBeanServer? I want to use the MemoryMX MBean to track the memory consumption.
I can connect to the JBoss MBeanServer using JNDI lookup but the java.lang.MemoryMX MBean is not registered with the JBoss MBeanServer.
EDIT: The requirement is for programmatic access to the memory usage from the client.
I wrote a class like this:
import javax.management.remote.JMXServiceURL; import javax.management.MBeanAttributeInfo; import javax.management.MBeanInfo; import javax.management.MBeanServerConnection; import javax.management.ObjectName; import javax.management.remote.JMXConnector; import javax.management.remote.JMXConnectorFactory; public class JVMRuntimeClient { static void main(String[] args) throws Exception { if (args == null) { System.out.println("Usage: java JVMRuntimeClient HOST PORT"); } if(args.length < 2) { System.out.println("Usage: java JVMRuntimeClient HOST PORT"); } try { JMXServiceURL target = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://"+args[0]+":"+args[1]+"/jmxrmi"); JMXConnector connector = JMXConnectorFactory.connect(target); MBeanServerConnection remote = connector.getMBeanServerConnection(); /** * this is the part where you MUST know which MBean to get * com.digitalscripter.search.statistics:name=requestStatistics,type=RequestStatistics * YOURS WILL VARY! */ ObjectName bean = new ObjectName("com.digitalscripter.search.statistics:name=requestStatistics,type=RequestStatistics"); MBeanInfo info = remote.getMBeanInfo(bean); MBeanAttributeInfo[] attributes = info.getAttributes(); for (MBeanAttributeInfo attr : attributes) { System.out.println(attr.getDescription() + " " + remote.getAttribute(bean,attr.getName())); } connector.close(); } catch(Exception e) { System.out.println(e.getMessage()); System.exit(0); } } } 
Unlike the JBoss server's MBeanServer, the JVM's MBean server doesn't allow remote monitoring by default. You need to set various system properties to allow that:
http://java.sun.com/javase/6/docs/technotes/guides/management/agent.html
A code example from an IBM article: link
MBeanServerConnection serverConn; try { //connect to a remote VM using JMX RMI JMXServiceURL url = new JMXServiceURL( "service:jmx:rmi:///jndi/rmi://<addr>"); JMXConnector jmxConnector = JMXConnectorFactory.connect(url); serverConn = jmxConnector.getMBeanServerConnection(); ObjectName objName = new ObjectName(ManagementFactory.RUNTIME_MXBEAN_NAME); // Get standard attribute "VmVendor" String vendor = (String) serverConn.getAttribute(objName, "VmVendor"); } catch (...) { } Have you tried launching a JConsole (is $JAVA_HOME/bin) to connect with the server? You should be able to view memory stats from there
The following code lists all mbeans of a given (jmx enabled) java application with their attributes and operations grouped by the domain. Just start the java app you wanna monitor with a fixed jmx port, e.g. by using these vm parameters:
-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=9000
-Dcom.sun.management.jmxremote.local.only=false
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=false
Then run this main:
import javax.management.*; import javax.management.remote.JMXConnector; import javax.management.remote.JMXConnectorFactory; import javax.management.remote.JMXServiceURL; import java.io.IOException; public class JmxListAll { public static void main(String[] args) throws IOException, MalformedObjectNameException, IntrospectionException, InstanceNotFoundException, ReflectionException { /* 1. JMXServiceURL. */ String jmxHost = "localhost:9000"; // exactly like jconsole localhost:9026 String url = "service:jmx:rmi:///jndi/rmi://" + jmxHost + "/jmxrmi"; JMXServiceURL serviceURL = new JMXServiceURL(url); /* 2. JMXConnector and the actual serverConnection */ JMXConnector connector = JMXConnectorFactory.connect(serviceURL); MBeanServerConnection serverConnection = connector.getMBeanServerConnection(); /* 3. Walk through the domains and their objects */ System.out.println("\n Now we have a look at " + serverConnection.getMBeanCount() + " mbeans!"); int objectCount = 0; for (String domain : serverConnection.getDomains()) { System.out.println("\n***********************************************************************************"); System.out.println("DOMAIN: " + domain); // query all the beans for this domain using a wildcard filter for (ObjectName objectName : serverConnection.queryNames(new ObjectName(domain + ":*"), null)) { System.out.println(" objectName " + ++objectCount + ": " + objectName); MBeanInfo info = serverConnection.getMBeanInfo(objectName); for (MBeanAttributeInfo attr : info.getAttributes()) { System.out.print(" attr: " + attr.getDescription()); try { String val = serverConnection.getAttribute(objectName, attr.getName()).toString(); System.out.println(" -> " + abbreviate(val)); } catch (Exception e) { System.out.println(" FAILED: " + e); } } for (MBeanOperationInfo op : info.getOperations()) { System.out.println(" op: " + op.getName()); } } } } static String abbreviate(String text) { if (text != null && text.length() > 42) { return text.substring(0, 42) + "..."; } else { return text; } } } As you should see, in the java.lang domain are several memory related mbeans. Pick the one you need.
