.odex What are they?

[thrillhouse847]

I see a lot about deodexing Android phones, and I see A LOT of .odex files in my system/app folder taking up space but what are .odex files? Why do/don't I need them? Can I move them to my backup folder on the sdcard or even just delete them, or do I have to use a rom for that? What's the benefit other than freeing up space?

 

[namebrandon]

Optimized .dex files. A .dex file is basically an aggregate of multiple classes.

Optimizing the dex file is just natively compiling it.. doing so obviously ties it to the specific hardware. This is why you don't take an odex file from a Droid 1 and put it on a Fascinate.

 

[thrillhouse847]

So when a rom claims to "deodex" what is it doing? Is it safe to move them away from their partner .apks?

 

[namebrandon]

So when a rom claims to "deodex" what is it doing? Is it safe to move them away from their partner .apks?

Long story-short, it's removing the "hardcoded" optimization, and relying on the hardware to optimize and cache it every time the application is launched. You unoptimize the .odex, repacking the results back into the .apk file. If that is done correctly, then yes, you technically no longer need the .odex. The device will the take the classes out, and attempt to optimize and cache them every time the application is launched.

De-odexing does the reverse of odexing. It increases hardware compatibility at the expense of performance.

 

[myester]

Long story-short, it's removing the "hardcoded" optimization, and relying on the hardware to optimize and cache it every time the application is launched. You unoptimize the .odex, repacking the results back into the .apk file. If that is done correctly, then yes, you technically no longer need the .odex. The device will the take the classes out, and attempt to optimize and cache them every time the application is launched.

De-odexing does the reverse of odexing. It increases hardware compatibility at the expense of performance.

That would make sense as to why I soft bricked my phone last week. I moved the odex file from the Captivate system dump for the Launcher to my fascinate. Thanks for the explanation on odex's!