To open a debug terminal, the front end opens a websocket at the URI defined for this. It receives every line to be shown in the terminal window as one message on the websocket. The M&C allows only one client to connect to the debug terminal at a time, opening the websocket may fail if either the M&C is down or if another user is already connected to the debug terminal (either from the Web-UI or from a Java client).
The URI to connect to the debug terminal is /debug&mncName=XXXXX
Where XXXXX has to be replaced with the name of the M&C to connect to. Once opened, the websocket transports every line from the debug terminal as a DebugMessage data object to the front end.