Oh, sorry this happens when making suggesting without testing them beforehand.
Sure, a Java Exception (OperatorException) can’t be caught by Python.
So, you need to catch RuntimeException for example.
I’ve once suggested similar here: How do you handle exceptions and warnings in snappy? - snap - STEP Forum (esa.int)
But I’m not sure at the moment if you can really get to the message of the Java exception.
Maybe you can investigate the exception you catch, which type is it and what attributes does it provide.
It could be that exceptions need to be handled differently in SNAPPY/JPY to provide more inforamtion.
If the above does not help I can only suggest to try your configuration on the command line with gpt and see if the error also occurs.