• UNEXPECTED: HttpStatus.INTERNAL_SERVER_ERROR → 500 (내부 서버 오류)
• BAD_REQUEST_EXCEPTION: HttpStatus.BAD_REQUEST → 400 (잘못된 요청)
• FORBIDDEN_EXCEPTION: HttpStatus.FORBIDDEN → 403 (접근 금지)
• NOT_FOUND_EXCEPTION: HttpStatus.NOT_FOUND → 404 (찾을 수 없음)
• UNAUTHORIZED_EXCEPTION: HttpStatus.UNAUTHORIZED → 401 (인증되지 않음)

{
    "success": false,
    "data": null,
    "error": {
        "code": "-1",
        "message": "Unexpected exception occurred : Group not found"
    }
}

{
    "success": true,
    "data": {

    },
    "error": null
}

{
    "success": true,
    "data": null,
    "error": null
}

{
    "success": false,
    "data": null,
    "error": {
        "code": "C001",
        "message": "Bad request"
    }
}

{
    "success": false,
    "data": null,
    "error": {
        "code": "C002",
        "message": "Forbidden"
    }
}

{
    "success": false,
    "data": null,
    "error": {
        "code": "C003",
        "message": "Not found"
    }
}

{
    "success": false,
    "data": null,
    "error": {
        "code": "C004",
        "message": "Unauthorized."
    }
}