Very good reference on using Jersey:
https://dennis-xlc.gitbooks.io/restful-java-with-jax-rs-2-0-en/cn/part1/chapter8/building_and_invoking_requests.html


Do note: need to do a string:
Response resp = invocationBuilder.post(Entity.entity(jsonObjectBody.toString(), MediaType.APPLICATION_JSON)); 

or else json
{"method":"Logon","payload":{"strLogin":"aaa_offers","strPassword":"gL(8KKw3L)\\\"g)BKR","elemParameters":{}},"schema":"xtk:session","securityToken":"","sessionToken":""}


will be converted to like NVP:

{

               "method": {

      "chars": "Logon",

      "string": "Logon",

      "valueType": "STRING"

    },

    "payload": {    

      "strLogin": {

        "chars": "aaa_offers",

        "string": "aaa_offers",

        "valueType": "STRING"

      },

      "strPassword": {

        "chars": "**** password here ****",

        "string": "**** password here ****",

        "valueType": "STRING"

      },

                 "elemParameters": {}

    },

    "schema": {

      "chars": "xtk:session",

      "string": "xtk:session",

      "valueType": "STRING"

    },

    "securityToken": {

      "chars": "",

      "string": "",

      "valueType": "STRING"

    },

    "sessionToken": {

      "chars": "",

      "string": "",

      "valueType": "STRING"

    }

  }