Jersey client testing

I have a Jersey client which performs post request to some black box service.
Also I have POJO mapping feature enabled.
My question is: how can I test this Jersey client?
I have integration tests already, they are calling real black box service.
Now I need to test black box service without calling real black box service.
Maybe there is some possibility to mock JSON response?

Environment: jersey-client and jersey-json versions - 1.19.1.