What is dalvik? - Fascinate Q&A, Help & Troubleshooting

Devs are always sayin to wipe dalvik when flashing a new ROM. I always wipe but idk wat I'm wiping...what is dalvik cache??
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DroiDAddicT14 said:
Devs are always sayin to wipe dalvik when flashing a new ROM. I always wipe but idk wat I'm wiping...what is dalvik cache??
Sent from my SCH-I500 using XDA App
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dalvik cache is a program cache area for the program dalvik. Dalvik is a java based virtual machine that is the bases for running your programs (the ones that have the .apk extension). In order to make access times faster (because there's not JIT (just in time) compiler installed by default), the dalvik-cache is the result of dalvik doing a optimization of the running program. Sounds confusing. It's similar to the prefetch files in Windows. -Andrizoid

And just FYI, you wipe the dalvik cache by booting into Clockworkmod and going to the advanced menu.
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Related

[Q] Wipe Dalvik Cache?

I know what happens when you do a factory reset/wipe, but what exactly happens if I only wipe Dalvik Cache? (I'm about to flash a ROM, don't want to do a complete factory reset/wipe, but wondering if I can still help "eliminate ghosts" by wiping Dalvik Cache.)
Bump, is this just like a crazy question or something?
What exactly does wiping Dalvik cache do?
trunkstar1 said:
Bump, is this just like a crazy question or something?
What exactly does wiping Dalvik cache do?
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dalvik is a virtual machine in android operating system that runs applications, which is similar java vm. dalvik builds some sort of cache of applications (i wouldn't go into details) to run them faster in dalvik cache space. you can clear them out, and android will rebuild the cache on the next boot. and the initial boot will take longer than usual once you wiped the dalvik cache because android needs to rebuild it.
So it's something that you can safely wipe on occasion right, just to clear up any bugs?
trunkstar1 said:
So it's something that you can safely wipe on occasion right, just to clear up any bugs?
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when you flash a custom rom, usually the rom automatically wipes out dalvik cache to remove all that junk from the previous rom.. you do not need to wipe it regularly unless you flash apps or any other system modifications on top of the existing rom via clockworkmod recovery very often
But is there any "harm" in doing it? Any consequences other than a longer reboot time?
trunkstar1 said:
But is there any "harm" in doing it? Any consequences other than a longer reboot time?
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Not at all. Apps will just be a little sluggish for a bit.
Sent from my SGH-T959 using XDA App
Using Kies to goto 2.2, does that wipes Dalvik cache? Koz I went to 2.2 from kies mini, then ODIN'd a Voodoo kernel and i never wiped it manually...
so should I?
many thanks
You are trying to not factory reset but any rom you will find will have a system, data, data_data and cache wipe built into it. You can try finding a Rom you like and remove the wipes from the update_script but those wipes are put there on purpose. Kies will wipe everything too.
or use root explorer go in to system and find dalvik cache and delete files =>
sir can i ask a question?
jaetm83 said:
dalvik is a virtual machine in android operating system that runs applications, which is similar java vm. dalvik builds some sort of cache of applications (i wouldn't go into details) to run them faster in dalvik cache space. you can clear them out, and android will rebuild the cache on the next boot. and the initial boot will take longer than usual once you wiped the dalvik cache because android needs to rebuild it.
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is it normal to boot so long when i accidentally wipe dalvik cache? because im afraid and thinking my phone was brick what can i do to turn it back normal? wait to boot the system?
avie14 said:
is it normal to boot so long when i accidentally wipe dalvik cache? because im afraid and thinking my phone was brick what can i do to turn it back normal? wait to boot the system?
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Yes it is normal for it to take longer than a normal bootup. It is rebuilding the Dalvik that was just wiped. #nosorcery
trunkstar1 said:
I know what happens when you do a factory reset/wipe, but what exactly happens if I only wipe Dalvik Cache? (I'm about to flash a ROM, don't want to do a complete factory reset/wipe, but wondering if I can still help "eliminate ghosts" by wiping Dalvik Cache.)
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Click to collapse
Thank you for this question, thank you guys now I know that wiping dalvik cache is not that bad at all.

Cygenomod nightly builds

When updateing a nightly build on CY 7 does it erase all apps and data
Sent from my SGH-I897 using XDA App
Not unless you choose to wipe Data. You can, and maybe should, clear Cache and Dalvik Cache though. This won't affect your apps/data etc.
don't need wipe,direct install is ok

Improve aokp rom performance

I recently flashed aokp carbon rom on my galaxy sl.
But the performance is weak. Is there any general settings for all aokp rom which will increase performance ? In the rom control option i go to scrolling cache if i need best scrolling what should i set it to
Force enable
Default enable
Default disable
or Force disable ?
thank you guys sorry i am noob
Default enable should do. If that still doesn't improve scrolling, try force enable. Just try the options for yourself and see, that's the best way. You need to give more details about your issue. Elaborate on the 'weak' performance. Also, did you wipe cache & dalvik cache before installing the ROM?
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No i was on cm9 before so i did not wipe anything. i directly installled. should i wipe dalvik cache and cache , factory reset ?
now i am on aokp so can i reinstall it again after wiping cche and dalvik cache ? will it mprove the perfomace ?
Change the kernel
sorry but there is only one kernel for ics any other suggestion ?
Yes. You should always wipe dalvik cache and cache when installing a new ROM. Even if it's just a version update of an already installed ROM. It's always better to wipe to avoid usual FC problems. Dalvik cache mainly. The only thing is that your phone will take around 5-6 minutes to boot the first time after you wipe dalvik cache, because it's rebuilding the cache. After that it'll boot normally every other time until you wipe dalvik cache again.
CM9 and AOKP are two different ROMs so when changing between them you should do a full wipe i.e. wipe everything (system, data, cache, dalvik cache and .android_secure folder on the SD card). Otherwise you'll get a lot of FCs. If you do a full wipe all your apps will be gone so you might want to take a Titanium Backup of them or just set them up again when they re-download automatically on the new ROM. Make sure to not restore data of any system apps using Titanium Backup in the new ROM. Once you install the AOKP ROM, upgrading to a newer version won't need a full wipe but only dalvik cache and cache wipe.
About the kernel, just use the one that came with your ROM.
Sent from my Desire HD using xda premium
wiping cache/dalvik are a must when flashing any new kernels

Difference between Dalvik Cache vs Normal Cache

I found same question in Dev forum but can't post as I'm still new. So I ask the same question here:
What is Davik Cache and what is normal Cache?
Are they the same thing or 2 different cache that must be wiped when flashing roms?
Normal Cache is any temporary information created or used by an app.
Dalvik Cache is a program cache area for the program dalvik. Dalvik is a java based virtual machine that is the bases for running your programs (the ones that have the .apk extension). In order to make access times faster (because there's not JIT (just in time) compiler installed by default), the dalvik-cache is the result of dalvik doing a optimization of the running program. Sounds confusing. It's similar to the prefetch files in Windows.
When you full wipe the normal cache is being deleted automaticly. Dalvik cache is being deleted manually via any recovery. Under Advanced in CWM.
Sent from my Nexus 10 using Tapatalk HD
thanks
thanks
Thanks, now I understand better. I was wondering where is this Dalvik Cache as I couldn't find the clearing function, so it is only found in custom Recovery mode.
What about my factory default phone? Its stock recovery show up as Android system recovery <3E>, there's a wipe cache partition function. I tried it and all my apps still working ok.
Thanks!

How can i do soft wiping?

Using flawless ics rom, and i started getting random reboots. Idk why, i didnt use titanium backup at all.
My apps are all useful right now so i dont wanna lose them. So how can i do like some soft wipe that doesnt delete all my apps? I dont want to do backups. Becoz it can lead to random reboot if i restore them.
Did wipe cache but no help.
Sent from my WT19i using xda app-developers app
Wipe Dalvik cache ...thats soft wipe...
Random reboots looks like more of kernel issue ...
The only things you can wipe without loosing data are cache and dalvik cache. But wiping dalvik cache won't change anything, because as far as I know the dalvik cache will be rebuilt on every boot
So try wiping cache or change the kernel for the rom
Sent from my Nexus 4 running Android 4.3
mihahn said:
The only things you can wipe without loosing data are cache and dalvik cache. But wiping dalvik cache won't change anything, because as far as I know the dalvik cache will be rebuilt on every boot
So try wiping cache or change the kernel for the rom
Sent from my Nexus 4 running Android 4.3
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Dalvik cache is rebuilt only on first boot or if an app is changed via recovery or if you upgrade to higher OS (like ics to JB)...
Some times it gets corrupted and wiping helps...(like 1 in 10 times...) and the cache gets rebuilt (android is upgrading....)
Cache is wiped whenever you reboot so it's one of the most pointless thing to do in recovery for stock roms..(wiping batteystats is the most pointless thing...)
On CM roms ,system dalvik lies in /cache so wiping cache is equivalent to wiping dalvik for system apps..
@OP
Use titanium backup to backup all apps and do a complete wipe..
karandpr said:
Dalvik cache is rebuilt only on first boot or if an app is changed via recovery or if you upgrade to higher OS (like ics to JB)...
Some times it gets corrupted and wiping helps...(like 1 in 10 times...) and the cache gets rebuilt (android is upgrading....)
Cache is wiped whenever you reboot so it's one of the most pointless thing to do in recovery for stock roms..(wiping batteystats is the most pointless thing...)
On CM roms ,system dalvik lies in /cache so wiping cache is equivalent to wiping dalvik for system apps..
@OP
Use titanium backup to backup all apps and do a complete wipe..
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give him a medal :good:

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