question: public static byte [ ] toByteArray ( String spacedHex ) { int idx = 0 ; final int len = spacedHex . length ( ) ; final StringBuilder sb = new StringBuilder ( ) ; final ByteArrayOutputStream bytes = new ByteArrayOutputStream ( ) ; while ( idx < len ) { final char chr = spacedHex . charAt ( idx ++ ) ; if ( chr != ' ' ) { sb . setLength ( 0 ) ; sb . append ( chr ) ; sb . append ( spacedHex . charAt ( idx ++ ) ) ; final int i = Integer . parseInt ( sb . toString ( ) , 16 ) ; final byte b = ( ( byte ) i ) ; bytes . write ( b ) ; } } return bytes . toByteArray ( ) ; }
target:  Convert the spaced hex form of a String into a byte array.