private static String createTempDirectory(String baseDir, String fileStem) {
        Long nano = new Long(System.nanoTime());
        return baseDir + File.separator + fileStem + nano;
    }
private static String createTempDirectory ( String baseDir , String fileStem ) { Long nano = new Long ( System . nanoTime ( ) ) ; return baseDir + File . separator + fileStem + nano ; }
Generate unique directory name of form:
basedir/fileStem<time-in-nanos>

@param baseDir
@param fileStem
@return unique dir name