public static byte[] convert(String digits) 
{
	ByteArrayOutputStream baos = new ByteArrayOutputStream();
	for (int i = 0; i <  digits.length(); i += 2) {
	    char c1 = digits.charAt(i);
	    if ((i+1)  >= digits.length())
		throw new IllegalArgumentException
		    (sm.getString("hexUtil.odd"));
	    char c2 = digits.charAt(i + 1);
	    byte b = 0;
	    if ((c1  >= '0') && (c1 < = '9'))
		b += ((c1 - '0') * 16);
	    else if ((c1  >= 'a') && (c1 < = 'f'))
		b += ((c1 - 'a' + 10) * 16);
	    else if ((c1  >= 'A') && (c1 < = 'F'))
		b += ((c1 - 'A' + 10) * 16);
	    else
		throw new IllegalArgumentException
		    (sm.getString("hexUtil.bad"));
	    if ((c2  >= '0') && (c2 < = '9'))
		b += (c2 - '0');
	    else if ((c2  >= 'a') && (c2 < = 'f'))
		b += (c2 - 'a' + 10);
	    else if ((c2  >= 'A') && (c2 < = 'F'))
		b += (c2 - 'A' + 10);
	    else
		throw new IllegalArgumentException
		    (sm.getString("hexUtil.bad"));
	    baos.write(b);
	}
	return (baos.toByteArray());
}

Convert a String of hexadecimal digits into the corresponding byte array by encoding each two hexadecimal digits as a byte.

 public static String convert(byte[] bytes) 
{
	StringBuffer sb = new StringBuffer(bytes.length * 2);
	for (int i = 0; i <  bytes.length; i++) {
	    sb.append(convertDigit((int) (bytes[i]  > > 4)));
	    sb.append(convertDigit((int) (bytes[i] & 0x0f)));
	}
	return (sb.toString());
}

Convert a byte array into a printable format containing a String of hexadecimal digit characters (two per byte).

 public static int convert2Int(byte[] hex) 
{
	// Code from Ajp11, from Apache's JServ
	// assert b.length==4
	// assert valid data
	int len;
	if(hex.length <  4 ) return 0;
	if( DEC[hex[0]]< 0 )
	    throw new IllegalArgumentException(sm.getString("hexUtil.bad"));
	len = DEC[hex[0]];
	len = len < <  4;
	if( DEC[hex[1]]< 0 )
	    throw new IllegalArgumentException(sm.getString("hexUtil.bad"));
	len += DEC[hex[1]];
	len = len < <  4;
	if( DEC[hex[2]]< 0 )
	    throw new IllegalArgumentException(sm.getString("hexUtil.bad"));
	len += DEC[hex[2]];
	len = len < <  4;
	if( DEC[hex[3]]< 0 )
	    throw new IllegalArgumentException(sm.getString("hexUtil.bad"));
	len += DEC[hex[3]];
	return len;
}

Convert 4 hex digits to an int, and return the number of converted bytes.