Gang! Welcome to the world of Mobility ~ here also we’ve something great called ‘JAVA’ so let’s get started with basics of Android platform for cell phones…….! So :P, First thing to be ask for ? What is Android ?

Android is a software stack for mobile devices….. that includes an operating system, middleware and key applications. The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language.

FYI: We’ll have posts on Android SDK and ENV. setup later…!

And now what is the …..? Android Application Fundamentals :

Android applications are written in the Java programming language. The Android SDK tools compile the code—along with any data and resource files—into an Android package, an archive file with an .apk suffix. All the code in a single .apk file is considered to be one application and is the file that Android-powered devices use to install the application.

Once installed on a device, each Android application lives in its own security sandbox:

• The Android operating system is a multi-user Linux system in which each application is a different user.
• By default, the system assigns each application a unique Linux user ID (the ID is used only by the system and is unknown to the application). The system sets permissions for all the files in an application so that only the user ID assigned to that application can access them.
• Each process has its own virtual machine (VM), so an application’s code runs in isolation from other applications.
• By default, every application runs in its own Linux process. Android starts the process when any of the application’s components need to be executed, then shuts down the process when it’s no longer needed or when the system must recover memory for other applications.