Android Utililty Methods String to Hex Byte Array Convert

String hexString = bytesToHexString(str.getBytes());
return hexStringToBytes(hexString);

if (hexString == null || hexString.equals("")) {
    return null;
hexString = hexString.toUpperCase();
int length = hexString.length() / 2;
char[] hexChars = hexString.toCharArray();
byte[] d = new byte[length];
for (int i = 0; i < length; i++) {
...

int m = 0, n = 0;
int l = src.length() / 2;
byte[] ret = new byte[l];
for (int i = 0; i < l; i++) {
    m = i * 2 + 1;
    n = m + 1;
    ret[i] = Byte.decode("0x" + src.substring(i * 2, m)
            + src.substring(m, n));
...

int len = hex.length() / 2;
byte[] result = new byte[len];
char[] achar = hex.toCharArray();
for (int i = 0; i < len; i++) {
    int pos = i * 2;
    byte b1 = (byte) "0123456789ABCDEF".indexOf(achar[pos]);
    byte b2 = (byte) "0123456789ABCDEF".indexOf(achar[(pos + 1)]);
    result[i] = (byte) (b1 << 4 | b2);
...

String[] hexArray = hexString.split(HEX_STRING_BLANK_SPLIT);
byte[] bytes = new byte[hexArray.length];
for (int i = 0; i < hexArray.length; i++) {
    String hex = hexArray[i];
    bytes[i] = Integer.valueOf(hex, 16).byteValue();
return bytes;

if (hexString == null || hexString.equals("")) {
    return null;
hexString = hexString.toUpperCase();
int length = hexString.length() / 2;
char[] hexChars = hexString.toCharArray();
byte[] d = new byte[length];
for (int i = 0; i < length; i++) {
...

byte[] buf = new byte[ids.length() / 2];
for (int i = 0, j = 0; i < buf.length; i++, j += 2) {
    byte h = (byte) ((byte) ids.charAt(j) - 0x30);
    byte l = (byte) ((byte) ids.charAt(j + 1) - 0x30);
    buf[i] = (byte) (h << 4 | l);
return buf;

if (null == s)
    return null;
return hexStringToBytes(s, 0, s.length());

if (null == hexString || offset < 0 || count < 2
        || (offset + count) > hexString.length())
    return null;
byte[] buffer = new byte[count >> 1];
int stringLength = offset + count;
int byteIndex = 0;
for (int i = offset; i < stringLength; i++) {
    char ch = hexString.charAt(i);
...

if (dataString.equals("")) {
    return null;
BigInteger dataPlus1BigInteger = new BigInteger("10" + dataString,
        16);
byte[] dataPlus1Bytes = dataPlus1BigInteger.toByteArray();
byte[] dataBytes = new byte[dataPlus1Bytes.length - 1];
System.arraycopy(dataPlus1Bytes, 1, dataBytes, 0, dataBytes.length);
...