Automate Thick Client through backend

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I have a requirement to automate some functionalities done by an executable JAR file. Presently people do the functionalities manually through the UI.

I was asked to automate the same functionalities not through UI. That tool does not provide any API support. So I need to automate through the protocol that the application uses, using some programming language.

Here are the challenges:

1. Need to find which end server, this application interacts with (ip address)
2. Need to find which protocol this application uses.
3. Need to find the parameter, the application uses while performing the request.

I thought to use Wireshark to capture the request. But without knowing the server ip & the type of protocol that the application uses ,I am unable to capture the traffic / identify the correct request, which was captured.

Please do the needful.