Make continuation servlet to log the incoming JSON in case of parsing errors

Sometimes the JSON parsing throws exceptions similar to this:

Caused by: java.lang.IllegalStateException: Unexpected '0' while seeking one of ',}'

or

Caused by: java.lang.IllegalStateException: Unexpected 'P' while seeking one of ',}'

and others exception of similar type as well.

It would be useful to know what is the full input to be able to debug what is going on.