question: public static boolean isBytecode ( InputStream is ) throws IOException { if ( ! is . markSupported ( ) ) throw new IOException ( "can only read input streams that support mark/reset" ) ; is . mark ( - 1 ) ; int first = is . read ( ) ; int second = is . read ( ) ; boolean rtn = ( first == ICA && second == IFE && is . read ( ) == IBA && is . read ( ) == IBE ) ; is . reset ( ) ; return rtn ; }
target:  check if given stream is a bytecode stream, if yes remove bytecode mark 