How to make ip address calculator with java netbeans

int prefix = Integer.valueOf(mask.getText());
int pos = prefix / 8; //important octet position
int rem = prefix % 8; //binary digit of importan octet

String binIpFull = "";
String subBinary = "";
String subBinaryFull = "";
String binnetidFull = "";
String binbcidFull = "";
String netmaskFull = "";
String netidFull = "";
String bcidFull = "";

//loop to generate binary mask from octet pos
for (int i = 1; i & lt; = 8; i++) {
 if (i & lt; = rem) {
  subBinary += "1";
 } else {
  subBinary += "0";
 }
}

//netmask (integer version of subBinary
int netmask = Integer.parseInt(String.valueOf(subBinary), 2);

//ip octets array
int[] oct = {
 Integer.valueOf(oct1.getText()),
 Integer.valueOf(oct2.getText()),
 Integer.valueOf(oct3.getText()),
 Integer.valueOf(oct4.getText())
};

//binary of important octet
String binOct = String.format("%8s", Integer.toBinaryString(oct[pos])).replace(' ', '0');

String binNetId = "";
String binBcId = "";

for (int i = 0; i & lt; 8; i++) {
 String binPointer = subBinary.substring(i, i + 1);
 if (binPointer.equals("1")) {
  binNetId += binOct.substring(i, i + 1);
  binBcId += binOct.substring(i, i + 1);
 } else {
  binNetId += "0";
  binBcId += "1";
 }
}

//loop to generate display-ready strings
for (int i = 0; i & lt; = 3; i++) {
 binIpFull += String.format("%8s", Integer.toBinaryString(oct[i])).replace(' ', '0');
 if (i < pos) { = ""
  subbinaryfull += "11111111"; = ""
  netmaskfull = "" += "255"
  binnetidfull = ""
  ','
  0 ');="" binbcidfull="" netidfull="" bcidfull="" ="" }else="" if(i="">pos){
  subBinaryFull += "00000000";
  netmaskFull += "0";
  binnetidFull += "00000000";
  binbcidFull += "00000000";
  netidFull += "0";
  bcidFull += "1";
 } else {
  subBinaryFull += subBinary;
  netmaskFull += String.valueOf(netmask);
  binnetidFull += binNetId;
  binbcidFull += binBcId;
  netidFull += Integer.parseInt(String.valueOf(binNetId), 2);
  bcidFull += Integer.parseInt(String.valueOf(binBcId), 2);
 }
 if (i != 3) {
  subBinaryFull += ".";
  netmaskFull += ".";
  binnetidFull += ".";
  binbcidFull += ".";
  netidFull += ".";
  bcidFull += ".";
  binIpFull += ".";
 }
}
subBinLabel.setText(subBinaryFull);
netMaskLabel.setText(netmaskFull);
netBinLabel.setText(binnetidFull);
bcBinLabel.setText(binbcidFull);
netIdLabel.setText(netidFull);
bcIdLabel.setText(bcidFull);
ipBinLabel.setText(binIpFull);