Android : android days between two datetimes

i have two datetime 09/01/2014 and 09/10/2014.i want to check days between there datetimes. i wrote function witch can to change datetime format

public static String dateFormatterforLukka(String inputDate) {

    String inputFormat = "MM/dd/yyyy";
    String outputFormat = "d MMM";

    Date parsed = null;
    String outputDate = "";
    try {
        SimpleDateFormat df_input = new SimpleDateFormat(inputFormat,
                new Locale("en", "US"));
        SimpleDateFormat df_output = new SimpleDateFormat(outputFormat,
                new Locale("en", "US"));


        parsed = df_input.parse(inputDate);
        outputDate = df_output.format(parsed);
    } catch (Exception e) {
        outputDate = inputDate;
    }
    return outputDate;
}

but i do not know how i can solve my problem if anyone knows solution please help me