What are the core building blocks of android ?

The core building blocks of android are:

• Activity - single screen on android mobile
• View
• Fragment 
• Services – like Network Operation 
•  Intent - To perform inter-communication between activities or services.
•  Resource Externalization - such as strings and graphics.
•  Notification signaling users - light, sound, icon, notification, dialog etc.
•  Content Providers - They share data between applications
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•  Permissions.PROCESS_OUTGOING_CALLS: Allows an application to monitor, modify, or abort outgoing calls.