III. DALVIK VIRTUAL MACHINE
As previously mentioned, Android is running on the
Linux kernel and its applications are written by Java
programming language, so Android applications are running
on a Java virtual machine named Dalvik virtual machine.
Dalvik virtual machine has been redesigned and optimized
by Google for the hardware features of mobile devices. In
Android system, there is a tool named dx, included in the
Android SDK, transforms the Java Class files (which
compiled by a regular Java compiler) into the .dex format.
The .dex format files integrate all Java class files and delete
redundant information in every Java class files. There are
several features of Dalvik virtual machine:
• Dalvik virtual machine could have multiple
instances on one device and every instance runs in a
separate Linux process, an Android application runs
in an instance of a Dalvik virtual machine.
• Dalvik virtual machine relies on the underlying
operating system (Linux kernel) for process
isolation, memory management and threading
support.
• Dalvik virtual is register-based.
The follow figure (figure3-1) shows the position of Dalvik virtual machine in Android system.
III. DALVIK VIRTUAL MACHINEAs previously mentioned, Android is running on theLinux kernel and its applications are written by Javaprogramming language, so Android applications are runningon a Java virtual machine named Dalvik virtual machine.Dalvik virtual machine has been redesigned and optimizedby Google for the hardware features of mobile devices. InAndroid system, there is a tool named dx, included in theAndroid SDK, transforms the Java Class files (whichcompiled by a regular Java compiler) into the .dex format.The .dex format files integrate all Java class files and deleteredundant information in every Java class files. There areseveral features of Dalvik virtual machine:• Dalvik virtual machine could have multipleinstances on one device and every instance runs in aseparate Linux process, an Android application runsin an instance of a Dalvik virtual machine.• Dalvik virtual machine relies on the underlyingoperating system (Linux kernel) for processisolation, memory management and threadingsupport.• Dalvik virtual is register-based.The follow figure (figure3-1) shows the position of Dalvik virtual machine in Android system.
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