How does Android System Track the Applications ? 

Android system assigns each application a unique ID that is called Linux user ID. This ID is used to track each application.

What are Dalvik Executable files ?

Dalvik Executable files have .dex extension and are zipped into a single .apk file on the device.

Can You Deploy Executable JARs on Android? Which Packaging is Supported by Android ?

No. Android platform does not support JAR deployments. Applications are packed into Android Package (.apk) using Android Asset Packaging Tool (aapt) and then deployed on to Android platform. Google provides Android Development Tools for Eclipse that can be used to generate Android Package.

Why Cannot You Run Standard Java Byte Code on Android ?

Android uses Dalvik Virtual Machine (DVM) which requires a special bytecode. We need to convert Java class files into Dalvik Executable files using an Android tool called "dx". In normal circumstances, developers will not be using this tool directly and build tools will care for the generation of DVM compatible files.

What is ANR ?

ANR stands for Application Not Responding. It is a dialog box that appears if the application is no longer responding.

What is NDK ?

NDK stands for Native Development Kit. By using NDK, you can develop a part of app using native language such as C/C++ to boost the performance.

What is ADB ?

ADB stands for Android Debug Bridge. It is a command line tool that is used to communicate with the emulator instance.