Many a times we want some task to be performed at some later time in future. For Example: In SMS Scheduler we want a SMS to be send at some later time, or Task Reminder in which we want to be reminded about a task at a particular time, to implement all these things we use AlramManager class.AlarmManager class provides access to the system alarm services. These allow you to schedule your application to be run at some point in the future. When an alarm goes off, the Intent that had been registered for it is broadcast by the system, automatically starting the target application if it is not already running. Registered alarms are retained while the device is asleep (and can optionally wake the device up if they go off during that time), but will be cleared if it is turned off and rebooted. The Alarm Manager holds a CPU wake lock as long as the alarm receiver's onReceive() method is executing. This guarantees that the phone will not sleep until you have finish...