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27

Dalvik VM (Virtual Machine) is Google's version of a Java VM (on which apps run). VMs keep apps isolated and independent from actual hardware and other apps. But, for this to work, Dalvik needs to convert so called bytecode (designed for virtual machine) to native machine code. In order to minimize the performance penalty that the bytecode to native code ...


18

I just did this! /data/property/persist.sys.dalvik.vm.lib is a textfile containing one of two values: 'libart.so' or 'libdvm.so'. You can change from ART to Dalvik simply by editing this file. Ex: adb shell 'echo libdvm.so >/data/property/persist.sys.dalvik.vm.lib'


17

ADB is close, but things like adb shell pm clear <package_name> to clear caches (and data, oops) from selected apps requires root (as would clearing Dalvik cache). But there's a similar approach to just wipe out all app caches (not Dalvik/ART, though): fastboot erase cache would do that with the device booted into the bootloader. Details can be found e....


14

Zygote isn't really bound up with Dalvik, it's just an init process. Zygote is the method Android uses to start apps. Rather than having to start each new process from scratch, loading the whole system and the Android framework afresh each time you want to start an app, it does that process once, and then stops at that point, before Zygote has done anything ...


12

In Android, every application runs as a separate user. In the Linux kernel, each process is owned by a single user, therefore it is not possible to run multiple Dalvik applications on a single Linux process. The overhead of running multiple Dalvik VM instance is lightweight because Linux fork() system call is copy-on-write, a write to a shared COW page will ...


10

Short answer: unless you've changed it yourself, it's Dalvik. Dalvik is currently the supported VM for Android. ART is a new VM, which is expected to become the supported one for the future L release. If you are using the L developer preview, you're using ART. In KitKat, there is a preview (an early beta version) of ART, which you can turn on from the ...


10

From the official Android Lollipop website, Android 5.0 provides a faster, smoother and more powerful computing experience. Android now runs exclusively on the new ART runtime, built from the ground up to support a mix of ahead-of-time (AOT), just-in-time (JIT), and interpreted code. It’s supported on ARM, x86, and MIPS architectures and is fully 64-bit ...


7

I finally figured it out, here's how I did it: Even though adb can't get root, and the phone it's self can't get root, as it turns out, there is in fact one more way to clear the cache without fully booting the phone. Turn the phone off Make sure you have fastboot working on your computer Press the power button on the phone and then hold down the volume ...


7

I think I see the source of your confusion. Dalvik VM isn't a virtual machine the same way as VMware or Virtualbox. In that kind of VM, VMware (or whatever) is pretending to be the whole computer. Every operation has to go through the VM, it has to be prevented from accessing the real hardware, and if it does access the real hardware, VMware has to do some ...


6

/data/property/persist.sys.dalvik.vm.lib contains the name of the runtime library you wish to use - libart.so or libdvm.so. So, you can switch back to Dalvik like so: adb shell 'echo libdvm.so >/data/property/persist.sys.dalvik.vm.lib' Source


6

As you mentioned you're using Magisk for root, I'm assuming you're running on Android 5 or up. The answer would be no. You can safely ignore the "Wipe Dalvik Cache" after OTA updating and re-rooting. Dalvik cache is compiled binary code (optimized DEX) for your installed applications, so it usually makes sense to wipe them if you removed/replaced your apps ...


5

As of this moment, it is a known fact (not necessarily an issue) that the Xposed framework DOES NOT WORK with ART. So, you either: Stay with Dalvik runtime, and get the advantage of using Xposed; OR Uninstall Xposed framework, and get the advantage of using ART After installing Xposed, the runtime gets reset from ART to Dalvik. Can you stop it please? ...


5

Each Dalvikvm process runs under a sand-boxed environment owned by the user id (uid) of the application running, it should be noted that upon installation of the application, the uid is allocated and assigned to each installed application. The net result is that each running application cannot trample another's process due to the different uid assigned, ...


5

You can. Understand that it's running Bionic rather than glibc, and not everything you're used to having on desktop Linux will be available. The simplest way to experience this is to shut the Android framework down with adb shell stop (while running as root). At this point, anything you can do on the device is being done without the VM. You can run ...


4

Found very insightful information on dalvik-cache at stackoverflow from reputed sources(Google's employees who worked on Dalvik virtual machine platform). Below is the summary of it, more from Android User's perspective in (hopefully) simple words. Where is dalvik-cache located in my Android device ? In a typical Android device, there is a directory named ...


4

That's unlikely to be possible. Dalvik cache is stored in /data/dalvik-cache, and doing an ls -l /data (as root) shows: drwxrwx--x system system 2013-03-29 14:54 dalvik-cache As you can see, it is owned by user system of the group system, and all other users only have "execute" permission (i.e. they are only permitted to change into that ...


4

Yes, you're right, Android 5.0 (and 5.1 for that matter) uses only ART.


4

No, you don't need to wipe it. It is probably still in recoveries because you could need it at some point, or developers just didn't remove it yet. For me, dalvik cache folder is empty.


4

The Dalvik Cache is still in use under ART, it is the location where the .oat files (they contain the compiled application, compiled during installation ) are stored, they just didn't change the name. Source: 1 So Wiping may be necessary if ART related files were updated. Because it does no harm other than compiling all applications again, I suggest just ...


3

The DEX file stored in dalvik-cache is an optimized ("odex") file. For historical reasons it carries the file extension ".dex". The canonical documentation on dexopt is in dalvik/docs/dexopt.html. It's a bit stale at this point but is a reasonable starting point.


3

The Dalvik VM isn't providing a security boundary, but the kernel is providing a security boundary in terms of the process the VM runs in. That's why, for example, it is no big deal for an Android application to run native code, which (more or less) by definition runs outside the VM. It's still in the process, and the kernel ensures that the process isn't ...


3

If you have root access, Using adb you can clear cache. rm -r /data/dalvik-cache rm -r /cache/dalvik-cache


3

You can run the Jar files using app_process, which replaces the java executable on Android. Looking at /system/bin/am for example, we see it's really running exec app_process $base/bin com.android.commands.am.Am "$@" You've mentioned running Xposed. If you'll google the manual installation of this framework, you'll see it both deploys a jar to /system/...


2

Of course you can. Although it seems like there's no problem to migrate dalvik-cache to a normal SD card filesystem (the most common, vfat), it still is highly recommended that you format your SD card to ext4 (or the same as your /data) to ensure everything works fine. So let's go. A full backup of all your apps is recommended before proceeding though if ...


2

There's absolutely no magic here caused by a mysterious "Dalvik Speed Patch". The Author said that in the comments himself by stating: Lol... I just mention dalvik speed patch, actually it's a kanged lib file... So it's just a wording issue that you took as a rumour. The higher Antutu benchmark scores are very propably caused by overcklocking using the ...


2

What you describe as "desktop", and the screenshot shows, is called by different names. Mostly it listens on the names Launcher and Homescreen, depending on the aspect referred to. And yes, it's an app that ships with its own .apk file, as all its "replacements" (e.g. Apex Launcher, GoLauncher, or Holo Launcher – to name some) do.


2

Just try it by yourself. I've felt no real difference. Maybe it is something that is device specific or there is just a very small difference. But it can change with Android 5.0 'L' because ART on Android 4.4 is some sort of beta version. Switching to ART is as easy as switching back to Dalvik. Settings > Developer Options > Select Runtime. There ...


2

No, they're different types of virtualization. The Dalvik VM works like an interpreter or just-in-time compiler: installed apps consist of Dalvik bytecode, but the CPU only knows how to run ARM or x86 machine code, so the DVM reads the Dalvik bytecode instructions and translates them into equivalent ARM or x86 instructions to make the app run. It's similar ...


1

On my Xperia M, running the latest nightly CM, it always causes trouble (every 10 seconds an app crashes), so I occasionally try it (Is it working yet? - No, well, I guess it's time to switch back), but I never use it - others say it's working fine for them. If you are able to switch to ART, I assume you are rooted and have a custom ROM installed, so you are ...


1

Erase userdata and reboot using fastboot. Resort to this method if you are ok loosing your data. Installing Fastboot on your Desktop/Laptop . Fastboot comes with android-sdk for windows. (make sure fastboot is installed) Boot your phone in fastboot mode Its generally done this way, press down volume key then power on button and hold them for 6-7 ...


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