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As a curious aside, if you bought an x86 powered smartphone or tablets running Android, it features ARM binary translation given that many apps with native elem

As a curious aside, if you bought an x86 powered smartphone or tablets running Android, it features ARM binary translation given that many apps with native elements included ARM native code but no x86. I did my own tests with it to find it achieving close to 100% performance. It's turtles all the way down.

qubex 9y ago
I thought that was achieved by having applications in Java bytecode with a Java virtual machine doing just in time compilation. In fact I thought that was the whole point of the Android ecosystem.
- my123 9y ago
  The Android NDK is heavily used - so you end up using native code apps anyway... libhoudini was Intel's dynamic translator for running ARM libs on x86 Android devices.
  - qubex 9y ago
    I never knew. That's quite interesting.
  - digi_owl 9y ago
    It is fully possible to produce architecture specific APKs, and the Play store will quietly hand over the one relevant to your device. https://www.apkmirror.com/apk/facebook-2/messenger/messenger-124-0-0-43-69-release/ https://www.apkmirror.com/apk/facebook-2/messenger/messenger... Note that there is one for ARM and one for x86.
- bitmapbrother 9y ago
  There is no Java bytecode or JVM on any Android device.
  - qubex 9y ago
    Can you explain? I thought Dalvik and ART are Java virtual machines. I'm no expert on Android but I thought this was widely known and accepted.
    - pjmlp 9y ago
      No, they make use of DEX bytecodes and depending on the specific Android version they are only pure interpreters, JIT, AOT compilers or a mix of everything with PGO. https://source.android.com/devices/tech/dalvik/ https://source.android.com/devices/tech/dalvik/ https://source.android.com/devices/tech/dalvik/jit-compiler https://source.android.com/devices/tech/dalvik/jit-compiler
      - qubex 9y ago
        I know ART features an AOT compiler... So basically they're not JVMs and Java bytecode but rather JVM and bytecode analogues that serve roughly the same purpose (post-Dalvik AOT ART notwithstanding).
    - bitmapbrother 9y ago
      ART is register based hybrid JIT/AOT runtime that was designed for memory constrained embedded devices. You cannot run Java applications on an Android device because ART is not compatible with the JVM and vice versa. Additionally, ART processes DEX bytecode and not Java bytecode.

qubex 9y ago

I thought that was achieved by having applications in Java bytecode with a Java virtual machine doing just in time compilation. In fact I thought that was the whole point of the Android ecosystem.

my123 9y ago
The Android NDK is heavily used - so you end up using native code apps anyway... libhoudini was Intel's dynamic translator for running ARM libs on x86 Android devices.
- qubex 9y ago
  I never knew. That's quite interesting.
- digi_owl 9y ago
  It is fully possible to produce architecture specific APKs, and the Play store will quietly hand over the one relevant to your device. https://www.apkmirror.com/apk/facebook-2/messenger/messenger-124-0-0-43-69-release/ https://www.apkmirror.com/apk/facebook-2/messenger/messenger... Note that there is one for ARM and one for x86.
bitmapbrother 9y ago
There is no Java bytecode or JVM on any Android device.
- qubex 9y ago
  Can you explain? I thought Dalvik and ART are Java virtual machines. I'm no expert on Android but I thought this was widely known and accepted.
  - pjmlp 9y ago
    No, they make use of DEX bytecodes and depending on the specific Android version they are only pure interpreters, JIT, AOT compilers or a mix of everything with PGO. https://source.android.com/devices/tech/dalvik/ https://source.android.com/devices/tech/dalvik/ https://source.android.com/devices/tech/dalvik/jit-compiler https://source.android.com/devices/tech/dalvik/jit-compiler
    - qubex 9y ago
      I know ART features an AOT compiler... So basically they're not JVMs and Java bytecode but rather JVM and bytecode analogues that serve roughly the same purpose (post-Dalvik AOT ART notwithstanding).
  - bitmapbrother 9y ago
    ART is register based hybrid JIT/AOT runtime that was designed for memory constrained embedded devices. You cannot run Java applications on an Android device because ART is not compatible with the JVM and vice versa. Additionally, ART processes DEX bytecode and not Java bytecode.