How to use this?

Fork/Clone/Download this project
In settings.gradle, change the rootProject.name
In build.gradle.kts, change group = "..."
In src/main/java/com/example/main.kt, change package com.example

How to build JAR?

Run Gradle task shadowJar with gradlew shadowJar
The JAR will be in build/libs/...-all.jar

... and after?

You can upload the JAR to AWS Lambda and starting playing with it! Enjoy! 😉