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java rmi jmx
Updated Fri, 28 Oct 2022 22:00:23 GMT

RMI disabled, Java still listens on port 1099


When I execute netstat -tupan, one of the entries is the following:

tcp        0      0 :::1099  :::*         LISTEN      8778/java

However, I have removed all settings concerning RMI and JMX from the options passed to Java when it starts. My questions are:

  1. Is RMI actually still enabled? I can connect to the port using telnet.
  2. If not, why does Java still listen on the port?

Edit: I blocked the port using netcat: nc -l 1099. This prompted an error on the application startup, and it turns out that I have an MBean in the application which was automatically picked up by Spring on startup and registered.

Solution

Here is the steps to trace the issue:

  1. Stop your application
  2. Run another application which listened on port 1099
  3. Start your application again
  4. java.net.BindException: Address already in use exception is thrown by the class that tries to listen on port 1099.

You can work on the issue based on the clue.


References