Convert time to milliseconds and add to another time

I have 2 hours to add up and store in a Long attribute called duration, so I do:

    String source1 = "05:15:30";
    String[] tokens1 = source1.split(":");
    int secondsToMs1 = Integer.parseInt(tokens1[2]) * 1000;
    int minutesToMs1 = Integer.parseInt(tokens1[1]) * 60000;
    int hoursToMs1 = Integer.parseInt(tokens1[0]) * 3600000;
    int total1 = secondsToMs1 + minutesToMs1 + hoursToMs1;

Then I add another hour:

    String source12 = "03:05:10";
    String[] tokens12 = source1.split(":");
    int secondsToMs12 = Integer.parseInt(tokens12[2]) * 1000;
    int minutesToMs12 = Integer.parseInt(tokens12[1]) * 60000;
    int hoursToMs12 = Integer.parseInt(tokens12[0]) * 3600000;
    int total12 = secondsToMs12 + minutesToMs12 + hoursToMs12;

and calculate the sum of both:

Long t = new Long(total1) + new Long(total12);

Now if I show the total again in hh:mm:ss format, the sum of both shows me:

String hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(t),
        TimeUnit.MILLISECONDS.toMinutes(t) % TimeUnit.HOURS.toMinutes(1),
        TimeUnit.MILLISECONDS.toSeconds(t) % TimeUnit.MINUTES.toSeconds(1)); 


System.out.print(hms);

10:31:00

but it would have to show me a total of:

08:20:40