CODEWITHSUNDEEP
javajmxjdmkopendmk
clay
clay

Reputation: 20430

JMX Connection Hangs

With the following super simple Java application:

class Main {
    static final private Logger logger = LoggerFactory.getLogger(Main.class);

    public static void main(String[] args) throws Exception {
        JMXServiceURL url = new JMXServiceURL(null, "localhost", 9999);
        logger.info("got JMXServiceURL");
        logger.info(String.format("JMXServiceURL=%s", url.toString()));

        try (JMXConnector connector = JMXConnectorFactory.connect(url)) {
            logger.info("got JMXConnector");
            MBeanServerConnection connection = connector.getMBeanServerConnection();
            logger.info("got MBeanServerConnection");
            logger.info(String.format("connection.getMBeanCount()=%d", connection.getMBeanCount()));
        }

        logger.info("exiting");
    }
}

I'm using a minimal build.gradle file with dependencies:

dependencies {
  implementation 'ch.qos.logback:logback-classic:1.2.3'
  implementation 'org.jvnet.opendmk:jmxremote_optional:1.0_01-ea'
}

Without the jmxremote_optional dependency, I get a java.net.MalformedURLException: Unsupported protocol: jmxmp error. I presume I've added the correct Maven dependency to resolve that.

When I run this, I get the following and then the application hangs indefinitely:

120     18:43:33.693 [main] INFO  jmxclient.Main - got JMXServiceURL
123     18:43:33.696 [main] INFO  jmxclient.Main - JMXServiceURL=service:jmx:jmxmp://localhost:9999

I definitely have a Java application exposing JMX metrics on that port:

time curl localhost:9999
curl: (52) Empty reply from server

real    0m0.020s
user    0m0.012s
sys 0m0.000s

Upvotes: 1

Views: 345

Answers (0)

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