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The layer above Linux kernel contains the Android native
libraries, which is written in C or C++, and is compiled for the
particular hardware architecture used by the phone.
Below are several of the most important libraries
1.
Surface Manager: This library allows drawing
commands go into off-screen bitmaps that are then
combined with other bitmaps to form the display the
user sees, which lets the system create all sorts of
interesting effects such as see-through windows and
fancy transitions.
2.
2D and 3D graphics: On Android, both two and three
dimensional elements can be combined in a single user
interface. This library will use 3D hardware if the
device has it or a fast software renderer if it doesn’t.
3.
Media codecs: Android can play and record both video
and audio in a variety of formats, such as AAC, AVC
(H.264), H.263, MP3, and MPEG-4.
4.
SQL database: Android includes SQLite database
engine for a persistent internal storage for applications.
5.
Browser engine: Android uses Webkit library for fast
display of HTML content. These libraries are not
standalone applications; they exist only to be called by
higher-level programs.
b.
Android Runtime
Android runtime is separated into two important parts:
1.
Dalvik virtual machine which runs DalvikExecuteable
(.dex) files, which are converted from the standard
.class and .jar files. The result is .dex files, which are
more compact and efficient than class files. These are
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