It appears that JDWP did not realize that eclipse unilaterally disconnected. If you check the connection status in the server you will see that it's still "ESTABLISHED":
From my experience it appears that within 20 minutes the OS realizes that the channel has been broken and port 8787 goes back to LISTEN status, which means it's ready ao accept new incoming connections.
If you don't feel like waiting for so long, and you're sure this action will not impact other users, you can do a "plt restart" which will be quicker. There might be a way to force the OS to update the port status but I couldn't find it. If someone knows of such a way, please share.