droidconIN 2016

The sixth edition of droidconIN

Chaitanya Nettem


Jack, Jill & Java 8

Submitted Sep 19, 2016

This talk will go over the new Jack and Jill toolchain & the new Java 8 features that they bring to Android land. You will learn about -

  • The existing Android toolchain of javac, dx, jarjar etc.
  • How Jack and Jill replace the existing toolchain
  • New Java 8 features that Jack brings
  • Drawbacks to Jack you should consider before upgrading


What are Jack and Jill (aka why should you care about this?)

Jack is Google’s new compiler/toolchain for Android. It compiles Java source into Android dex bytecode. It will replace the current javac, ProGuard, jarjar, and dx toolchain.

The talk will cover

  • How both toolchains work
  • What Jack & Jill do differently
  • Why you should upgrade to Jack
  • What some of Jack’s cons are

Jack vs javac+dx

  • Legacy javac toolchain: javac (.java → .class) → dx (.class → .dex)
  • New Jack toolchain: Jack (.java → .dex)
  • We’ll cover details about how both work

How to enable Jack?

  • Go over changes required in build.gradle if you wish to try out Jack
  • Cover some gradle options that Jack provides

Reason why you want to upgrade - Java 8 features

Features compatible back to Gingerbread

(these use anonymous classes and hence are compatible back to Gingerbread)

  • Lambdas
  • Method References
  • Type annotations
Features supported in Nougat and beyond
  • Stream APIs
  • Interfaces - default method implementations & static methods
  • Repeatable annotations

Reasons why you might not want to upgrade

  • Transform API is not yet supported. This means that some libraries do not yet work with Jack. The most prominent example being RealmDB. Bugs filed here and here
  • Lint detectors which operate on a Java bytecode level will not work since there is no intermediate bytecode when you use Jack.
  • Jack is currently slower than javac + dx

Speaker bio

I have been working on Android apps for the past 2 years. I am currently a freelance developer who works with Android and Python. You might know me from other events like PyCon 2014 where I presented a poster on Creating a Fall Detector using Raspberry Pi and Python or from my Android apps like, Search for Reddit.

  • chaitanya.im




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droidconIN is an annual conference on Android, part of the worldwide series of events. more