Apps Should I use a Timer or an Alarm manager?

[GIR]

Hello,

I have a chunk of code in my app that needs to be executed on the 1/4 hour, every hour, but I'm unsure which method to use.

Thanks to google Im now aware that I can use either a Timer or the Alarm manager.

I found an alarm example, which I can modify to run my code every 15 minutes from the time my app starts running, but I'm stuck getting it to run *on* the quarter hour:

Intent myIntent = new Intent(AlarmndsActivity.this, MyAlarmService.class);
pendingIntent = PendingIntent.getService(AlarmndsActivity.this, 0, myIntent, 0);
                  
AlarmManager alarmManager = (AlarmManager)getSystemService(ALARM_SERVICE);

Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.add(Calendar.SECOND, 10);
                  
alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);

whereas if I use my own timer I have to:
A) check if the minutes is either 0,15,30 or 45
B) test/set a flag to make sure the code is run only once per 15 minute period
C) prevent my app from sleeping and kill the battery.

Any guidance hugely appreciated,
GIR