"64k out to be enough for anyone"

64k method limit talk @ DC Droids meetup

1. Mike Evans LivingSocial @m_evans10
2. “640K ought to be enough for anybody.”
3. –Dalvik Developers “64K ought to be enough for anybody.”
4. Dalvik?
5. Dalvik?
6. Dalvik The VM that runs Android. Optimized for mobile devices.
7. Java/Scala/Clojure/etc Compiler (.jar) .class files JAVA ARCHITECTURE
8. .class files classes.dex Java/Scala/Clojure/etc Compiler dex (.apk) ANDROID ARCHITECTURE
9. Java/Scala/Clojure/etc Compiler dex optimizer (odex) zipalign proguard ANDROID ARCHITECTURE classes.dex (.apk) .class files
10. Okay…what’s the problem?
11. Unable to execute dex: method ID not in [0, 0xffff]: 65536 ! Conversion to Dalvik format failed: Unable to execute dex: method ID not in [0, 0xffff]: 65536 PROBLEM:
12. https://source.android.com/devices/tech/dalvik/dex-format.html public final class IndexMap { … public final short[] typeIds; public final short[] protoIds; public final short[] fieldIds; public final short[] methodIds; …
13. So what can we do?
14. SOLUTION #0:
15. ART? SOLUTION #1:
16. SOLUTION #2: Proguard Java class file shrinker, optimizer and obfuscator ! Detects and removes unused classes, fields, methods and attributes
17. SOLUTION #3: Refactor code so that code can be isolated into 2nd dex Modify classpath during runtime Allow access to methods via reflection ! Facebook did this in 2011 Secondary DEX file
18. SOLUTION #3: Secondary DEX file Refactor code so that code can be isolated into 2nd dex Modify classpath during runtime Allow access to methods via reflection ! Facebook did this in 2011
19. MultiDexApplication BRAND NEW
20. MultiDexApplication Native in Lollipop ! Part of support library (all the way to Donut!) ! Not supported officially in developer tools…yet BRAND NEW
21. an egregious hack
22. a clever solution an egregious hack
24. $ ./dex-method-counts LivingSocial.apk ! Read in 65490 method IDs. <root>: 65490 : 3 android: 6837 accessibilityservice: 6 bluetooth: 2 … https://github.com/mihaip/dex-method-counts
25. GPS: 14K methods - collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and so forth. 23k methods - Basically all of Google’s services. You’ll have a hard time making a compelling app that lives in the Google Play ecosystem without it. GUAVA:
26. $ gradle app:dependencies —configuration “compile” ! compile - Classpath for compiling the main sources. +--- com.squareup.picasso:picasso:2.3.3 +--- com.jakewharton:butterknife:5.1.2 +--- com.squareup.retrofit:retrofit:1.6.1 | \--- com.google.code.gson:gson:2.2.4 -> 2.3 \--- de.hdodenhof:circleimageview:1.2.0 … ! BUILD SUCCESSFUL GUAVA:
27. ads analytics cast auth drive games push location maps wallet wearable … A clever way for Google to provide support for its many services APIs, all the way back to Gingerbread Google Play Services: {
28. GAMES DRIVE ADS CAST
29. https://gist.github.com/MichaelEvans/71150c93577de6f5ab0a Custom Gradle Task - After compilation of .class files Unzip the original google-play-services rm [plus|games|drive|cast] re-zip a new jar Inject new jar into dependency tree ??? Profit
30. $ ./dex-method-counts LivingSocial.apk ! Read in 40364 method IDs. <root>: 40364 : 3 android: 6837 accessibilityservice: 6 bluetooth: 2 …
31. Questions?