android restart app programmatically

Intent mStartActivity = new Intent(context, StartActivity.class);
int mPendingIntentId = 1234;

PendingIntent mPendingIntent = PendingIntent.getActivity(context, mPendingIntentId,    mStartActivity, PendingIntent.FLAG_CANCEL_CURRENT);
AlarmManager mgr = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
mgr.set(AlarmManager.RTC, System.currentTimeMillis() + 100, mPendingIntent);

System.exit(0);