jConsole guide for simple connection

Today i was trying to do memory analysis on a remote tomcat and I faced some issues while setting up the jConsole. Here I am documenting all the issues I faced and the solutions to these issues:-Note : This setup is for the simple development environment with one  user. For more advanced case like enabling the security refer here

 Enable and configure JMX agent on the remote VM:


These are the properties i set in my tomcat setenv.sh and this file does not exist by default in the tomcat 7 so I had to create it:

export CATALINA_OPTS="$CATALINA_OPTS -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.authenticate=false
 -Dcom.sun.management.jmxremote.ssl=false -Djava.rmi.server.hostname=remotehostip"

Issues Faced

Here are the issues which I faced before I arrived to the above configuration:

Issue 1:  Read Access must be restricted

This error I recived on that startup of tomcat.

Password file read access must be restricted: /opt/jdk1.7.0_51/jre/lib/management/jmxremote.password
 Solution: Do as the error says, give only the read access to the password file
chmod 600 jmxremote.password

Issue 2: java.rmi.server.ExportException

On tomcat shutdown I used to get this exception 

Error: Exception thrown by the agent : java.rmi.server.ExportException: Port already in use: 8999; nested exception is: 

java.net.BindException: Address already in use
And I had to so sudo kill tomcatpid.
Solution: The solution to this error was to set the jmx properties on CATALINA_OPTS and this way it only is executed on startup
   Wrong way of doing it:
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=8999"
  Right way:
CATALINA_OPTS="$CATALINA_OPTS -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false -Djava.rmi.server.hostname="

After this change tomcat shuts down without any errors

Issue 3 : jConsole on the client machine not connecting

Solution :Here is what you can do to debug the issue:

Start jConsole with this command that enables the logging in jconsole.

jconsole -J-Djava.util.logging.config.file=\temp\jmx\log\logging.properties remote-host-ip:8999
Here is the sample logging.properties that I used:
handlers = java.util.logging.ConsoleHandler
.level = INFO  

// Level FINEST is suitable for diagnosing SSL-related JMX remote
// connection issues.
So you will see a log console opening with jconsole and you will have better idea why it is not connection.After enabling the logging i found out that jconsole was not printing the correct ip for remote host, so I introduced this property


where remotehostip is the ip of the system on which tomcat is running.

  I had to add this property because the hostname was not correctly setup on the vm running tomcat. You can see it by running the following command in the console:

hostname -i

If this command does not return the actual ip of the system then the hostname is not setup correctly. You can either setup the hostname correctly or use the above property. After that change the jConsole started connecting.

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