Right now, the only way to manage a running server is through JMX.

Using jconsole, the JMX URL on the advanced tab would be service:jmx:rmi://localhost:(jmx listening port)/jndi/rmi://localhost:(jmx listening port) +1/server. You must log in as the sysadmin user.

 Example if JMX is enabled on port 9393:
 JMX URL: service:jmx:rmi://localhost:9393/jndi/rmi://localhost:9394/server
 User Name: sysadmin
 Password: 123

If JMX is not enabled on your JVM by default, enable it by adding the jmxremote property when starting Java:

java -Dcom.sun.management.jmxremote ...