I have an SF application which has a stateless service. The Stateless service is currently having its Configuration defined in JSON format.I would like to host 2 instances of that application and each having different value for a key in this json configuration ?. I know it is possible for configurations in Settings.xml by specifying overrides while creating Application instance, but is their a way i can achieve something similar for JSON Configurations. ?
No, config overrides only work with Settings.xml.
Even then, config overrides flow down from application parameters, which means you can only set overrides per application, not per service within an application.
Services can be given an arbitrary byte array called "initialization data" during creation time. But this does not flow down into configuration files, and it cannot be changed or updated or upgraded later - you only get to set initialization data for a service once.