Increment time with 12 hour clock from AM to PM

I am trying to increment a time value and getting odd results:

 private String getNextTime(String time) {

        final int INTERVAL = 1;

        SimpleDateFormat df = new SimpleDateFormat("HH:mm a", Locale.US);           /
        Date d = null;                                                              
        try {
            d = df.parse(time);
        } catch (ParseException e) {
            System.out.println("Bad tee time: " + time);
            System.exit(-1);
        }
        Calendar cal = Calendar.getInstance();                                      
        cal.setTime(d);                                                             
        cal.add(Calendar.MINUTE, INTERVAL);                                         
        String outTime = df.format(cal.getTime());                                  
        return (outTime);                                                           
    }

If I input 11:59 AM the result is 12:00PM. If I input 12:59 PM I am expecting 01:00 PM, but get 13:00 PM. If I input 01:00 PM, I am expecting 01:01 PM, but get 01:01 AM. How do I get this to work correctly with a 12 hour clock?

SimpleDateFormat and Date are obsolete and buggy. Use the more modern classes from the java.time package.

DateTimeFormatter dtf = DateTimeFormatter.ofPattern("h:mm a", Locale.US));
LocalTime ldt = LocalTime.of(9, 0);
for (int h = 1; h < 10; h++) {
    System.out.println(ldt.format(dtf));
    ldt = ldt.plusHours(h);
}

prints

9:00 AM
10:00 AM
12:00 PM
3:00 PM
7:00 PM
12:00 AM
6:00 AM
1:00 PM
9:00 PM

Default Locale will be used if not specified. And use "hh:mm a" if you want leading zeros for single digit hours.

Never mind.

Change:

SimpleDateFormat df = new SimpleDateFormat("HH:mm a", Locale.US);

to:

SimpleDateFormat df = new SimpleDateFormat("hh:mm a", Locale.US);