Android runtime

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Android runtime
Basic data

developer Google Inc.
operating system Android
programming language C , C ++
category Runtime environment
License Apache license 2.0
source.android.com/devices/tech/dalvik/art.html

Android Runtime ( ART for short ) is a runtime environment that is used by Google's mobile operating system Android from version 5.0 Lollipop .

Previously, it was included as an experimental runtime environment in Android 4.4 KitKat and officially replaced the Dalvik virtual machine used until then as of Android 5.0 . Dalvik converted the Dex - byte code of an application in the native instruction set of the processor (usually ARM) to which was subsequently executed by the runtime environment of the device. Since Dalvik relied on just-in-time compilation , the bytecode had to be converted each time the application was called, which caused a delay in execution, so a correspondingly large cache was used so that this delay only occurred when the application was started for the first time that has not been used in a long time. In corresponding tests on the same device, the advantage of ART over Dalvik turned out to be less than hoped.

ART, on the other hand, converts the Dex bytecode once and already during the installation of an application with the help of the dex2oat tool into native binary code . This largely avoids delays when starting an application. By eliminating just-in-time compilation, the processor is used less, which should be noticeable in lower energy consumption. Applications designed for the Dalvik runtime environment are usually ART compatible.

Support for 64-bit applications on corresponding processor types was no longer added in Dalvik and is only available in ART. Even should the garbage collection , the garbage collection will now start less often and work faster than it was under Dalvik.

On the other hand, the disadvantage is the longer duration of the installation of applications and, when comparing the two compilation procedures, the increased memory consumption by an average of 20 percent.

Web links

Commons : Android Runtime  - collection of images, videos and audio files

Individual evidence

  1. ↑ NOTICE - platform / art - Git at Google . Retrieved December 5, 2014.
  2. ^ ART and Dalvik . Retrieved July 10, 2016.
  3. ↑ a b ART vs Dalvik - introducing the new Android runtime in KitKat . December 4, 2013. Retrieved December 5, 2014.
  4. ↑ Jörg Thoma: Lollipop runs faster without Dalvik and longer with Volta . November 19, 2014. Retrieved December 5, 2014.
  5. ↑ Jakob Straub: ART: The Turbo of Android 4.4 KitKat . November 10, 2013. Retrieved December 5, 2014.