Client.java

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.management.MBeanServerConnection;
import javax.management.Notification;
import javax.management.NotificationListener;
import javax.management.ObjectName;
import javax.management.remote.JMXConnectionNotification;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;

public class Client {
    public static void run(String url) throws Exception {
        final int notifEmittedCnt = 10;
        final CountDownLatch counter = new CountDownLatch(notifEmittedCnt);
        final Set<Long> seqSet = Collections.synchronizedSet(new HashSet<Long>());
        final AtomicBoolean duplNotification = new AtomicBoolean();

        JMXServiceURL serverUrl = new JMXServiceURL(url);

        ObjectName name = new ObjectName("test", "foo", "bar");
        JMXConnector jmxConnector = JMXConnectorFactory.connect(serverUrl);
        System.out.println("client connected");
        jmxConnector.addConnectionNotificationListener(new NotificationListener() {
            @Override
            public void handleNotification(Notification notification, Object handback) {
                System.out.println("connection notification: " + notification);
                if (!seqSet.add(notification.getSequenceNumber())) {
                    duplNotification.set(true);
                }
                if (notification.getType().equals(JMXConnectionNotification.NOTIFS_LOST)) {
                    long lostNotifs = ((Long)((JMXConnectionNotification)notification).getUserData()).longValue();
                    for(int i=0;i<lostNotifs;i++) {
                        counter.countDown();
                    }
                }
            }
        }, null, null);
        MBeanServerConnection jmxServer = jmxConnector.getMBeanServerConnection();

        jmxServer.addNotificationListener(name, new NotificationListener() {
            @Override
            public void handleNotification(Notification notification, Object handback) {
                System.out.println("client got: " + notification);
                if (!seqSet.add(notification.getSequenceNumber())) {
                    duplNotification.set(true);
                }
                counter.countDown();
            }
        }, null, null);

        System.out.println("client invoking foo (" + notifEmittedCnt + " times)");
        for(int i=0;i<notifEmittedCnt;i++) {
            System.out.print(".");
            jmxServer.invoke(name, "foo", new Object[]{}, new String[]{});
        }
        System.out.println();
        try {
            System.out.println("waiting for " + notifEmittedCnt + " notifications to arrive");
            if (!counter.await(30, TimeUnit.SECONDS)) {
                throw new InterruptedException();
            }
            if (duplNotification.get()) {
                System.out.println("ERROR: received duplicated notifications");
                throw new Error("received duplicated notifications");
            }
            System.out.println("\nshutting down client");
        } catch (InterruptedException e) {
            System.out.println("ERROR: notification processing thread interrupted");
            throw new Error("notification thread interrupted unexpectedly");
        }
    }
}