Rosjava nodes are not shutdown with ROS command rosnode kill

[wmlynar]

Hi,

when prototyping with rosjava it is very convenient to be able to kill the nodes with rosnode kill command. This is because you only need to know the node name, not the PID, etc. However when I issue ros command

rosnode kill node_name

RosJava node does not properly shutdown, despite that I see the message in the console

Feb 11, 2019 11:57:13 AM org.ros.internal.node.xmlrpc.SlaveXmlRpcEndpointImpl shutdown
INFO: Shutdown requested by /rosnode with message "user request"

Looking into the code org.ros.internal.node.server.SlaveServer there is a comment from damonkohler that the functionality is not yet implemented

public class SlaveServer extends XmlRpcServer {

...

  // TODO(damonkohler): This should also shut down the Node.
  @Override
  public void shutdown() {

...

}

I am adding this issue to attach it to the pull request with proposed simple implementation of the solution.

Thanks