Download link for icontrol jar

I don't believe you have to for iControl REST. You can use regular API requests via HTTP, no specific librbary or such needed. Have a look at:

https://clouddocs.f5.com/api/icontrol-rest/

If you are working from a specific programmaing language and have question please reply with which one.

For iControl SOAP it would strongly wonder why you want to use it, it has been deprecated in TMOS 11.6, which is quite old. If you start doing something new, focus on REST.