Choose any you’ll get comfortable with and add it to your system paths. In order to run our dex-tools we’ll need to have Java setup. Setup Kotlincįirst of all we’ll need to download kotlinc - Kotlin compiler for command line. Here we’ll go through some practical guide on how to get used to new tools and see the resulting bytecode. Also I encourage you to read content of the links in this article as they will be useful for broader understanding. And I highly recommend anyone who is interested to read them. This article was inspired by series of posts about d8 and r8 by Jake Wharton. In this article we’ll try to look at some examples on how to investigate what will be the result of compiling our code. So, as you can see from the compilation start till the time when we have our dex file there are quite a lot of tools which can work: kotlinc, javac, r8.

also now we have r8 tool which adds additional optimizations to d8.

dex file dex tool was used, now it is replaced with d8 tool. dex files from it there are additional things to note: And that new runtime is compatible with dex.īut that’s not all - between compiling our code to. After that we have new Android Runtime (ART) with a lot of different optimizations. This is so called Dalvik bytecode.ĭalvik Virtual Machine is where Android apps were run prior to Lollipop. Before running on Android all the compiled code (.class files) are compiled into.

But one thing about analyzing such bytecode is that actually it won’t be run on the device. This way we might see some additional classes instantiated, or variables etc. In order to get some insight on the performance and memory we can look at Java bytecode (or decompile from it to. This might lead to some overheads in memory and performance if used without caution (for example excessive usage of lambdas with parameters without inlining might produce a lot of anonymous classes and put additional pressure on GC).

Whenever we use some cool feature from Kotlin (say High-order functions) under the hood (when running on JVM) the feature is implemented in terms of Java bytecode. Modern Android development is based on Kotlin, which is interoperable with Java.

Java source code is compiled into