JConsole - Constant Disconnects with localhost/Kafka Sandbox

Question

I am trying to use JConsole to monitor/view metrics for Kafka Sandbox with Docker containers. As soon as I connect to locahost:35000, I receive the error: "Secure Connection Failed: Retry Insecurely?"

If I click Insecure connection, the connection works for a split second and then disconnects again with a different error: "Connection Lost: Reconnect?".

I've researched and tried many different combinations of JMX arguments, including the arguments below and none have worked so far.

The actual exception returned in the debug log is:

java.lang.SecurityException: Expecting a sun.rmi.server.UnicastRef2 remote reference in stub!

Has anyone been able to fix this issue with JConsole?

Current arguments used:

jconsole -debug -J"-Dcom.sun.management.jmxremote=true, -Dcom.sun.management.jmxremote.authenticate=false, -Dcom.sun.management.jmxremote.ssl=false, -Djava.rmi.server.hostname=localhost,  -Dcom.sun.management.jmxremote.local.only=false, -Dcom.sun.management.jmxremote.rmi.port=35000, -Dcom.sun.management.jmxremote.port=35000, -Dcom.sun.management.jmxremote.port=35000"

Java Info:

java 14.0.1 2020-04-14
Java(TM) SE Runtime Environment (build 14.0.1+7)
Java HotSpot(TM) 64-Bit Server VM (build 14.0.1+7, mixed mode, sharing)

Docker Info:

CONTAINER ID   IMAGE                                      COMMAND                  CREATED      STATUS                  PORTS                                          NAMES
b21d9589e737   mongodb-kafka-base-setup-mongod:1.0        "bash -c 'sleep 10 &…"   4 days ago   Exited (0) 4 days ago                                                  mongo1-setup
c0a23e041e23   mongodb-kafka-base-mongod:1.0              "docker-entrypoint.s…"   4 days ago   Up 4 days               0.0.0.0:35001->27017/tcp                       mongo1
7c56b4ccc89a   confluentinc/cp-kafka-rest:7.2.2           "/etc/confluent/dock…"   4 days ago   Up 4 days               8082/tcp                                       rest-proxy
3b6fd1821270   confluentinc/cp-schema-registry:7.2.2      "/etc/confluent/dock…"   4 days ago   Exited (1) 4 days ago                                                  schema-registry
c303de030d9f   confluentinc/cp-kafka-connect-base:7.2.2   "/etc/confluent/dock…"   4 days ago   Up 4 days (healthy)     8083/tcp, 9092/tcp, 0.0.0.0:35000->35000/tcp   connect
4c1665f78d4c   confluentinc/cp-kafka:7.2.2                "/etc/confluent/dock…"   4 days ago   Up 4 days               9092/tcp                                       broker
b707c2d6b8be   confluentinc/cp-zookeeper:7.2.2            "/etc/confluent/dock…"   4 days ago   Up 4 days               2181/tcp, 2888/tcp, 3888/tcp                   zookeeper

Netstat Info:

  TCP    0.0.0.0:35000          0.0.0.0:0              LISTENING
  TCP    [::]:35000             [::]:0                 LISTENING
  TCP    [::1]:35000            [::]:0                 LISTENING

You'll need to show your docker run command or compose files. Otherwise, this doesn't seem like a problem specific to any image (kafka, or otherwise). — OneCricketeer, Jan 08 '23 at 16:01
Perhaps the docker container doesn't bind to that port? `docker ps -a` or `netstat -anp | grep 35000` may show a clue.. — murtiko, Jan 08 '23 at 19:48
@murtiko I've updated the post with the Docker/Netstat info. Looks like port 35000 is correct. When I look at the logs on the Docker side, the error just says `WARNING: The server has decided to close this client connection.` — user2966445, Jan 08 '23 at 20:08
Yes it looks like the port is correctly configured and being listened on. Strange, maybe [this other question/thread](https://stackoverflow.com/questions/29412072/how-to-access-spring-boot-jmx-remotely) may help. It may not be a problem but i noticed that you provide the jmx related JVM args to jconsole? Afaik these parameters are needed for the vm that you want to monitor, and not jconsole. — murtiko, Jan 09 '23 at 10:00
@murtiko Updating to JDK 19 fixed this issue for me. Just posted the answer. — user2966445, Jan 09 '23 at 18:13

score 0 · Accepted Answer · answered Jan 09 '23 at 18:12

The fix for this issue was to update JDK to the latest version (in my case, JDK 19). After downloading/installing JDK 19 and running the updated JConsole, I no longer had the constant disconnects.

https://www.oracle.com/java/technologies/downloads/#jdk19-windows

JConsole - Constant Disconnects with localhost/Kafka Sandbox

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