Hexadecimal utils

HexUtils.java

public class HexUtils {
  private static final char[] HEX_CHARS = "0123456789ABCDEF".toCharArray();
  private static final String HEX = "0123456789ABCDEF";

  /**
  * Convert byte array to hexadecimal string
  * @param data Input array
  * @return hexadecimal string
  */
  public static String toHexString(byte[] data) {
    StringBuilder result = new StringBuilder();

    if (data != null) {
        for (byte octet : data) {
            int firstIndex = (octet & 0xF0) >>> 4;
            int secondIndex = octet & 0x0F;
            result.append(HEX_CHARS[firstIndex]);
            result.append(HEX_CHARS[secondIndex]);
        }
    }

    return result.toString();
  }
  
  /**
  * Convert hexadecimal string to byte array
  * @param text Input hexadecimal text
  * @return Byte array
  */
  public static byte[] hexStringToByteArray(String text) {
    int length = text.length();
    byte[] result = new byte[length / 2];

    for (int i = 0, j = 0; i < length; i += 2, j++) {
      char firstChar = text.charAt(i);
      int firstIndex = HEX.indexOf(firstChar);
      char secondChar = text.charAt(i + 1);
      int secondIndex = HEX.indexOf(secondChar);

      int octet = firstIndex << 4 | secondIndex;
      result[j] = (byte) octet;
    }

    return result;
  }


}