[JS] Implementing Checksum in Java

const DATA_LEN = 7;
HEADER_LEN = 2;
var data = [START_SYS, START_SYS, CMD1, CMD2, VAL1, VAL2, VAL3];

var checksum,
  sum = 0;

for (var i = HEADER_LEN; i < DATA_LEN - HEADER_LEN; i++) sum += data[i];

checksum = ~sum;
data.push(checksum);

const DATA_LEN = 7;
HEADER_LEN = 2;

var sum = 0,
  i = 0,
  result;

for (i = HEADER_LEN; i < DATA_LEN - HEADER_LEN; i++) sum += recievedData[i];

sum += recievedData[i]; //수신된 checksum을 더함
result = ~sum;

if (result == 0) console.log("NO ERROR IN TRANSMISSION");
else console.log("ERROR DETECTED");