Vitaliy Orlov

str.replaceAll("^(\\d{4})-(\\d{2})-(\\d{2})$", "$3-$2-$1"));

str.replaceAll("^(\\d{2})-(\\d{2})-(\\d{4})$", "$3-$2-$1"));

String input = "Thu Jun 18 20:56:02 EDT 2009";
        SimpleDateFormat parser = new SimpleDateFormat("EEE MMM d HH:mm:ss zzz yyyy");
        Date date = parser.parse(input);
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
        String formattedDate = formatter.format(date);