Find Previous Date using Days

private String previouDate(int days) {

    String current_date = "", previous_date = "";
    Calendar c = Calendar.getInstance();
    //System.out.println("Current time => " + c.getTime());

     SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd"); //define your formate for date    

    current_date = df.format(c.getTime());
    previous_date = getCalculatedDate("yyyy-MM-dd", -days);
    return previous_date;
}

private static String getCalculatedDate(String dateFormat, int days) {
    Calendar cal = Calendar.getInstance();
    SimpleDateFormat s = new SimpleDateFormat(dateFormat);
    cal.add(Calendar.DAY_OF_YEAR, days);
    return s.format(new Date(cal.getTimeInMillis()));
}