You have invalid formatted json message.
First of all you cannot use [ ] because according json specification is assumes that this will be an array.
You have to change these entries to the object ones { }.
You have to manually parse it, BTW as a plain string, or make json message valid and use libraries - GSON or Jackson
Here is valid json that I would use in your case
{
"agentCode": 9911223344,
"transId": 337450,
"resultCode": 0,
"resultDesc": "Transaction Successful",
"dealList": [{
"id": 1,
"value": "EST1"
}, {
"id": 2,
"value": "EST2"
}, {
"id": 3,
"value": "EST3"
}]
}