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

static String toHex ( byte [ ] data ) { StringBuffer sb = new StringBuffer ( data . length * 2 ) ; for ( int i = 0 ; i < data . length ; i ++ ) { sb . append ( hexc [ ( data [ i ] > > 4 ) & 0x0f ] ) ; sb . append ( hexc [ data [ i ] & 0x0f ] ) ; } return sb . toString ( ) ; }
convert a byte array to a hex string for debugging purposes
