Identify Java jdwp Debugger Assigned (Ephemeral) Port

Question

I am using the following JVM parameters to start-up a JVM with the hostpot debugger.

-Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=0

Answer 1

From within VM:

    Properties props = sun.misc.VMSupport.getAgentProperties();
    System.out.println(props.getProperty("sun.jdwp.listenerAddress"));

From outside application:

    VirtualMachine vm = com.sun.tools.attach.VirtualMachine.attach(PID);
    try {
        Properties props = vm.getAgentProperties();
        System.out.println(props.getProperty("sun.jdwp.listenerAddress"));
    } finally {
        vm.detach();
    }

Both are not a part of a standard. Applicable only to OpenJDK / Oracle JDK.