Simple CLI written in Kotlin that compiles to native code using GraalVM Native Image.
I love Go - it is simple, compiles to a small, statically linked binary, starts and runs very fast with minimal resources.
I also love Kotlin because it is a very expressive Java-based language with great features and a strong standard library.
One of the most exciting things going on in the Java world is GraalVM and especially GraalVM Native Image. It compiles Java Bytecode ahead-of-time to produce native (& optionally statically linked) binaries similar to Go.
In this project, I write a simple CLI application in Kotlin and compile it using GraalVM Native Image, trying to get the best of both worlds - write Kotlin, get Go-like binaries.
Working with GraalVM Native Image is not very smooth, it takes long to compile and some things just
don't work with it and/or requires additional configuration (reflect-config.json etc.).
The goal of this project is for me to try to do different things with native-image and track its progression. I can see what works out-of-the-box, what needs additional configuration and what does not work at all.
It can also serve as an example of how to configure native-image builds for Kotlin in Maven.
List of things I have tried so far:
- Basic file IO ✅
- Basic network IO (HTTPS) ✅
- Data classes ✅
- Log4j2 ❌
Make sure you have GraalVM >=21.3.0 installed.
If you are using Mac & Homebrew:
brew install --cask graalvm/tap/graalvm-ce-java17
sudo xattr -r -d com.apple.quarantine /Library/Java/JavaVirtualMachines/graalvm-ce-*Point your JAVA_HOME and GRAALVM_HOME env variables are set to point to it.
Example (in your .bashrc or .zshrc):
export GRAALVM_HOME=/Library/Java/JavaVirtualMachines/graalvm-ce-<YOUR_GRAALVM_VERSION>/Contents/Home
export JAVA_HOME=$GRAALVM_HOME
To compile, test and produce a .jar (not a native binary):
./mvnw clean packageTo compile, run native tests and produce a native binary:
./mvnw -P native clean packageTo skip tests:
./mvnw -DskipTests -P native clean package