@CheckReturnValue @Nonnull static public String hexStringFromBytes(@Nonnull byte[] bytes){
  StringBuilder sb=new StringBuilder();
  for (int i=0; i < bytes.length; i++) {
    sb.append(HEX_CHARS[(bytes[i] & 0xF0) >> 4]);
    sb.append(HEX_CHARS[bytes[i] & 0x0F]);
    sb.append(' ');
  }
  return sb.toString();
}

@ CheckReturnValue @ Nonnull static public String hexStringFromBytes ( @ Nonnull byte [ ] bytes ) { StringBuilder sb = new StringBuilder ( ) ; for ( int i = 0 ; i < bytes . length ; i ++ ) { sb . append ( HEX_CHARS [ ( bytes [ i ] & 0xF0 ) > > 4 ] ) ; sb . append ( HEX_CHARS [ bytes [ i ] & 0x0F ] ) ; sb . append ( ' ' ) ; } return sb . toString ( ) ; }
create a string containing hexadecimal values from a byte [ ] .
