How to get hour/minute difference in java

Question

I have to get total minutes between two hour.

17:00 and 16.06 hrs

If I do like

 17.00-16.06 =0.94 

but correct answer is 54 minutes.

so logically how can I get difference minutes from two time.

without using Calender api or Joda Time.

Code:

private  double getTimeDifference(Date startDate,Date endDate, boolean sameDay)
    {
                double startTimeF=Double.valueOf(startDate.getHours()+"."+startDate.getMinutes());
                double endTimeF=Double.valueOf(endDate.getHours()+"."+endDate.getMinutes());
                double totalTime=0;
                boolean isCalculated=false;
                for(double workTime:timeMap.keySet())
                {
                        double endTimeC=timeMap.get(workTime);

                        if(startTimeF>=workTime && startTimeF<=endTimeC)
                        {
                            if(endTimeF<endTimeC && sameDay)
                            {
                                isCalculated=true;
                                totalTime+=endTimeF-startTimeF;
                            }
                            else
                            {
                                totalTime+=endTimeC-startTimeF;
                            }
                            break;
                        }
                }

                for(double workTime:timeMap.keySet())
                {
                        double endTimeC=timeMap.get(workTime);
                        if(endTimeF>=workTime && endTimeF<=endTimeC)
                        {
                            if(!isCalculated)
                            {
                                if(workTime<startTimeF && sameDay)
                                {
                                    totalTime+=endTimeF-startTimeF;
                                }
                                else
                                {
                                    totalTime+=endTimeF-workTime;
                                }
                            }

                        }
                        else if(!sameDay)
                        {
                            totalTime+=endTimeC-workTime;
                        }
                }
                return totalTime;
    }

Time map contains key and value of json string:

{"time":[{"startTime":"8:00", "endTime":"12:30", "type":"Working"},{"startTime":"12:31", "endTime":"13:00", "type":"Break"},{"startTime":"13:01", "endTime":"17:00", "type":"Working"}]}

Answer 1

long milliDifference = date1.getTime() - date2.getTime();
long minuteDifference = TimeUnit.MINUTES.convert(milliDifference, TimeUnit.MILLISECONDS);

where date1 and date2 are of type java.util.Date.