question: public static void writeHexString ( ByteBuffer buffer , String hexStr ) throws IOException { char [ ] hexChars = hexStr . toCharArray ( ) ; if ( ( hexChars . length % 2 ) != 0 ) { throw new IOException ( "Hex string length must be even" ) ; } for ( int i = 0 ; i < hexChars . length ; i += 2 ) { String tmpStr = new String ( hexChars , i , 2 ) ; buffer . put ( ( byte ) Integer . parseInt ( tmpStr , 16 ) ) ; } }
target:  Writes a sequence of hexidecimal values into the given buffer, where every two characters represent one byte value.