With DEA's, you can't. With Diego, you can look at the new TCP routing
support [1] if you want the port to be accessible to everyone, all the
time, or ssh port forwarding [2] if you only want someone in the developer
role to access the imx port.

For the latter, you can look at [3] for an example of how to configure the
JVM and how to use the port forwarding mechanisms of the client.

[1]: https://github.com/cloudfoundry-incubator/routing-api-cli
[2]: https://github.com/cloudfoundry-incubator/diego-ssh
[3]: http://sykesm.mybluemix.net/posts/jmx-in-diego/

--
Matthew Sykes
matthew.sykes(a)gmail.com