Rest API ACCEPT和Content-Type

I was trying to hit a rest API URL which using POST request. It receives "ACCEPT" as "application/json" and "Content-Type" as "application/xml". The response from sever says "Content-Type → application/octet-stream;charset=UTF-8". But what now am getting is some kind of encrypted text as below

N4+8ByEFqdMY+fgXAeMQIe93TUKGNXerqeWOGDWm3IoDK5j7YysPB93ebN3IOBCOXlSOlkOV7Vr6 Cz0+nQnWVp09OmB1Xbazz33uWZrJqzzZ8Z7Zdnj0ZfIWMPKDKrymhR8SbXODr+DPj2b3Mv6kI8uo Q3Bx+AtQ8pCVqZQ5sutIOGvJdLhHNSLDNoWZOs87i3eDjGUobNUEiJFaavfKF7l4XJTtVng2TAqN VU9SF5PAlq16syqxTQ2qdk/NU+BOBv8mIYpoCn5gRhuNgpqyPI3b/EhRHLTCo23gRSTi6vwPHeQf vLLTEqtXJnE80xRNyRc9/XvnxBXzaCuW5JJ19GtBzzeJjRwf79WxFbdR50KTgt98T4fpzT42BWJa 6E7w/D7kH+kPO4GkhR6pB7JsC/PBxahvFsEV2tR1dQpCtWQUI9nmMt85bazfRwY4zOWWS5I/rZdN snKn2Zq+Xc2nzIG+imbAoSjIlp8+m/FSzB5fezLHF91fwTM/D1oDUaia11uLtqN8s1pHaH4K8Vkm Ll6pT5KEe+wqZD92gYiEButwXJpxKW4lEhTRdUtffU/6

How can I read it into plain text for some form of readable text like JSON or XML?

try using below line:-

response.setCharacterEncoding("utf-8");