Inforbiro is an Information Technology and Marketing Agency with its own Internet marketing network BlicKlik. We have a lot of experience in software development as well as in Internet marketing and advertising. We constantly try not only to develop great web sites, mobile, desktop or facebook applications but also to share our knowledge.
The byte order mark (BOM) is a Unicode character used to signal the endianness (byte order) of a text file or stream. BOM use is optional, and, if used, should appear at the start of the text stream.
Beyond its specific use as a byte-order indicator, the BOM character may also indicate which of the several Unicode representations the text is encoded in.
The UTF-8 representation of the BOM is the byte sequence 0xEF,0xBB,0xBF. A text editor or web browser interpreting the text as ISO-8859-1 or CP1252 will display the characters  for this.
The main tools is Android SDK (software development kit). It contains libraries, debugger, documentation and tutorials, Android emulator and you can get it on http://developer.android.com/sdk/index.html
After downloading the Android SDK from http://developer.android.com/sdk/index.html, unzip the content into desired folder (e.g. /opt/android-sdk on Ubuntu or any other GNU/Linux distribution).
The ADT (or Android Development Tools) is an extension to the Eclipse IDE (Integrated Development Environment).
The ADT plugin has support for the creation and debugging of Android applications.
Here are some of the features you could use in Eclipse after installing the ADT:
An AVD is an emulator instance that enables you to model an actual device and it is used for running and testing your Android applications.
Each AVD consists of a hardware profile; a mapping to a system image; as well as emulated storage, such as a secure digital (SD) card. You can create as many AVDs as you want in order to test your applications with several different configurations. This testing is important to confirm the behavior of your application when it is run on different devices with varying capabilities.