Why the callback server always listens to 25334 by default

Why the callback server always listens to 25334 by default, which will cause the pyspark applications to not run on the same server at the same time.
I tried to modify the listening port before starting the callback server like below:

**scala_utils.py**
`
self.gateway.start_callback_server(callback_server_parameters = CallbackServerParameters(port = 0))
`

this can work on the different port for each pyspark application, but the Checks Failure with the constraint_message:

`Can't execute the assertion: Error while obtaining a new communication channel`

Does anyone have any suggestions on this issue ?

Empieza en scala_utils.py, en la invocación de callback_server_parameters, y reproduce dos aplicaciones PySpark ejecutándose en el mismo servidor. Compara el puerto predeterminado del servidor de callbacks con port=0 y sigue la assertion resultante del canal de comunicación. Se considera terminado cuando las aplicaciones concurrentes pueden usar puertos de callback distintos sin Checks Failure.

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