What Android is not?

A Java ME implementation — Android applications are written using the Java language,
but they are not run within a Java ME (Mobile Edition) VM, and Java-compiled classes and
executables will not run natively in Android.
Part of the Linux Phone Standards Forum (LiPS) or the Open Mobile Alliance (OMA) —
Android runs on an open-source Linux kernel, but, while their goals are similar, Android’s
complete software stack approach goes further than the focus of these standards-defining
organizations.
Simply an application layer (such as UIQ or S60) — Although Android does include an application
layer, “Android’’ also describes the entire software stack, encompassing the underlying
operating system, the API libraries, and the applications themselves.
A mobile phone handset — Android includes a reference design for mobile handset manufacturers,
but there is no single “Android phone.” Instead, Android has been designed to support
many alternative hardware devices.
Google’s answer to the iPhone — The iPhone is a fully proprietary hardware and software
platform released by a single company (Apple), whereas Android is an open-source
software stack produced and supported by the Open Handset Alliance (OHA) and designed
to operate on any compatible device.

More recently, Android has expanded beyond a pure mobile phone platform to provide a development
platform for an increasingly wide range of hardware, including tablets and televisions.
Put simply, Android is an ecosystem made up of a combination of three components:

• A free, open-source operating system for embedded devices

• An open-source development platform for creating applications

• Devices, particularly mobile phones, that run the Android operating system and the applications
• created for it

More specifically, Android is made up of several necessary and dependent parts, including the
following:

• A Compatibility Definition Document (CDD) and Compatibility Test Suite (CTS) that
• describe the capabilities required for a device to support the software stack.

• A Linux operating system kernel that provides a low-level interface with the hardware, memory
• management, and process control, all optimized for mobile and embedded devices.

• Open-source libraries for application development, including SQLite, WebKit, OpenGL, and
• a media manager.

• A run time used to execute and host Android applications, including the Dalvik Virtual
• Machine (VM) and the core libraries that provide Android-specific functionality. The run
• time is designed to be small and efficient for use on mobile devices.

• An application framework that agnostically exposes system services to the application layer,
• including the window manager and location manager, databases, telephony, and sensors.
• A user interface framework used to host and launch applications.

• A set of core pre-installed applications.

• Native Android Applications x 5

• A software development kit (SDK) used to create applications, including the related tools,
• plug-ins, and documentation.

Most of the applications we create in Android will fall into one of the following categories:
Foreground Applications — The application which is only useful when appears on the screen and if it is suspended will not be visible like Game apps.

Background Application — These type of application only works at background of phone software. It does not show their visibility, most of its lifetime hidden like alarm clock.

Intermittent Applications — It works at both foreground and background. This type of application do most of their work in the background. Most well-designed applications fall into this category. A common example would be a media player.

Widgets and Live Wallpapers Apps — Some applications are represented only as a home-screen
Widget or as a Live Wallpaper.