1. What is Android ?

Ans:

It is an open-sourced operating system that is used primarily on mobile devices, such as cell phones and tablets. It is a Linux kernel-based system that’s been equipped with rich components that allows developers to create and run apps that can perform both basic and advanced functions.

2. What is the Android Architecture ?

Ans:

Android Architecture is made up of 4 key components:
a). Linux Kernel
b). Libraries
c). Android Framework
d). Android Applications

3. What are the features of Android architecture?

Ans:

Android architecture refers to the various layers in the Android stack. It consists of operating systems, middleware, and applications. Each layer in the Android architecture gives different services to the layer just above it.
The five layers present in the Android stack are:
a). Linux Kernel - It is responsible for device drivers, device management, memory management, power management, and resource access.
b). Libraries - There are a set of libraries having open-source Web browser engine WebKit, well-known library libc, libraries to play and record audio and video, SQLite database for sharing of application data and storage, SSL libraries for internet security, etc.
c). Android Runtime - There are core libraries along with DVM (Dalvik Virtual Machine) or ART(Android RunTime) as runtime which is helpful for running an Android application. DVM is optimized for mobile devices. DVM provides fast performance and consumes less memory. Replacing DVM, ART(Android RunTime) virtual machine was introduced to execute android apps from Android lollipop 5.0 version (API level 21).
d). Android Framework - It consists of Android APIs like UI (User Interface), resources, content providers (data), locations, telephony, and package managers. It provides interfaces and classes for the development of Android applications.
e). Android Applications - Applications like home, games, contacts, settings, browsers, etc. uses the Android framework that will make use of Android runtime and libraries.

4.What is an activity?

Ans:

Activity in java is a single screen that represents GUI(Graphical User Interface) with which users can interact in order to do something like dial the phone, view email, etc.
For example, the Facebook start page where you enter your email/phone number and password to log in acts as an activity.

5.What is a service in Android?

Ans:

Service is an application component that facilitates an application to run in the background in order to perform long-running operations without user interaction. A service can run continuously in the background even if the application is closed or even after the user switches to another application.

6. What are the Android Development Tools ?

Ans:

the Top 5 Android Development tools currently trending in the market.
a). Android SDK
b). Native Development Kit (NDK)
c). Titanium Mobile SDK
d). Hypernext Android Creator
e). ADOBE AIR