How to connect to a java program on localhost jvm using JMX?

Question

I should connect to a java program on localhost jvm using JMX. In other words I want to develop a JMX client to config a java program on localhost.

• Don't recommend using JConsole! JConsole is not suitable because it is general JMX client and have negative effect on main program performance.

• Samples on oracle site use RMIConnector and host:port params but I don't know: where should set jmx port?

• JConsole have an option to connect to java processes by PID. But I don't find any method in JMX api that have PID as input param.

Answer 1

We use something like the following to programatically connect to our JMX servers. You should run your server with something like the following arguments:

-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.port=1234 -Dcom.sun.management.jmxremote.ssl=false 

To bind to a particular address you'll need to add the following VM arguments:

-Djava.rmi.server.hostname=A.B.C.D 

Then you can connect to your server using JMX client code like the following:

String host = "localhost";  // or some A.B.C.D int port = 1234; String url = "service:jmx:rmi:///jndi/rmi://" + host + ":" + port + "/jmxrmi"; JMXServiceURL serviceUrl = new JMXServiceURL(url); JMXConnector jmxConnector = JMXConnectorFactory.connect(serviceUrl, null); try {    MBeanServerConnection mbeanConn = jmxConnector.getMBeanServerConnection();    // now query to get the beans or whatever    Set<ObjectName> beanSet = mbeanConn.queryNames(null, null);    ... } finally {    jmxConnector.close(); } 

We also have code that can programatically publish itself to a particular port outside of the VM arguments but that's more fu than you need I think.

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In terms of connecting "by pid", you need to be using Java6 to do it from Java land as far as I know. I've not used the following code but it seems to work.

List<VirtualMachineDescriptor> vms = VirtualMachine.list(); for (VirtualMachineDescriptor desc : vms) {     VirtualMachine vm;     try {         vm = VirtualMachine.attach(desc);     } catch (AttachNotSupportedException e) {         continue;     }     Properties props = vm.getAgentProperties();     String connectorAddress =         props.getProperty("com.sun.management.jmxremote.localConnectorAddress");     if (connectorAddress == null) {         continue;     }     JMXServiceURL url = new JMXServiceURL(connectorAddress);     JMXConnector connector = JMXConnectorFactory.connect(url);     try {         MBeanServerConnection mbeanConn = connector.getMBeanServerConnection();         Set<ObjectName> beanSet = mbeanConn.queryNames(null, null);         ...     } finally {         jmxConnector.close();     } } 

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I've also the author of SimpleJMX package which makes it easy to start a JMX server and publish beans to remote clients.

// create a new server listening on port 8000 JmxServer jmxServer = new JmxServer(8000); // start our server jmxServer.start(); // register our lookupCache object defined below jmxServer.register(lookupCache); jmxServer.register(someOtherObject); // stop our server jmxServer.stop(); 

It does have a client interface as well but right now it doesn't have any mechanisms to find processes by PID -- only host/port combinations are supported (in 6/2012).