Jack and Jill, new compilers for Android – unocero

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Jack and Jill is the new build tool, which comes in the latest installment of the Android SDK 21.1, but so far Google has decided to explain what and what exactly makes. Jack is the Android Java Compiler Kit (Americans love acronyms) is Jack and Jill Intermediate Linker Library. As I write this they are still “experimental”

The idea is simple:. Jack compile the java code directly to .dex, an executable in the Dalvik virtual machine. The compilation process takes source code and uses the compiler standard java, javac, to convert Java bytecode and off it goes through the compile dex to turn it into bytecode Dalvik first.

new compiler Jack does this job without using Java bytecode. Also apply some optimization and obfuscates via e Proguard. This is a simple one-step process and Google expected to have more advantages in the future, with features such as incremental compilation, for example. One could then say that in the end Android has its own compiler

Note that the .dex resulting code can be fed to Dalvik engine or the newest ART -. Android Runtime engine, which uses compile ” Ahead of time “, which is what we always called” compilation “, which is the .dex convert to native code at installation time program code. This can be much faster as well.

Jill meanwhile protects Jack having to see and process Java bytecode. If you have a library in Java, Jill converrtirá the .jar library in a .jack library with a format that Jack himself can come up with the rest of the object code.

At the moment the user must enable support for Jack and Jill if you want to use. This means adding “useJack = true” to build the Gradle file. There are more details in the Android development site.

Many wonder to realize what Google is moving Jack and Jill. The answer might be to seek tene run optimized compiler that can even make, as mentioned, incremental compilation. Another reason would move Dalvik and Java infrastructure to make demands for Oracle no longer be accommodated and certainly no longer a problem. Not using javac and Dalvik could well put distance between technology Android demands Java

However, Jack and Jill do not support. & Lt; java 8 and any updates should be made and implemented by Google . When Android was new, be compatible with Java and its infrastructure was what was sought. Today it seems that the trend is precisely rid of Java ..

References

Jack and Jill