{
  "order": {
    "shop": {
      "sell": {
        "1": 123213,
        "3": 27
      },
      "buy": {
        "1": 3,
        "2": 2
      },
     },
    "site": {
      "sell": {
        "1": 1,
        "3": 7
      },
      "buy": {
        "1": 4,
        "2": 2213
      },
     }
  }
}

{
  "order": {
    "shop": {
      "sell": {
        "1": 123213,
        "3": 27
      },
      "buy": {
        "1": 3,
        "2": 2
      },
      "price": 1234
    },
    "site": {
      "sell": {
        "1": 1,
        "3": 7
      },
      "buy": {
        "1": 4,
        "2": 2213
      },
      "price": 1234
    }
  }
}

Map response = new HashMap<>() {{
            put("order", ordersBuy.stream().collect(
                    groupingBy(
                            Order::getType,
                            groupingBy(
                                    Order::getCategory, toMap(Order::getIndex, Order::getPercent)
                            )
                    )
                )
            );
        }};