Services in Android

A service is an application component that can run some long running task in the background without the need for a user interface.

NOTE: Services run in the main thread of their hosting process.

Why Services in Android?:
A Service is use :

• to tell the system about something our application wants to be doing in the background.
  
• to expose some of its functionality to other Components of our Application.
  
• to expose some of its functionality to other third party Applications.
  

Forms of Service:

• Unbound(Started) Service:
  When an appliction component start an service by calling startservice() method, service is called started service.
  
• Bound Service:
  When an appliction component start an service by calling bindservice() method, service is called bound service.