This will download all the dependency jars (and in turn their dependencies too) into the current directory. You need to blank settings.gradle file in the same directory. It works with gradle 7.

apply plugin: 'application'

repositories {
  mavenCentral()
}

dependencies {
  implementation 'org.xerial:sqlite-jdbc:3.40.0.0'
}

task copyToLib(type: Copy) {
  into "."
  from configurations.runtimeClasspath
}

build.dependsOn(copyToLib)

Then run gradle build.

Here's a basic build.gradle file you need to compile kotlin. It can go in a directory with a blank settings.gradle file.

plugins {
  id 'org.jetbrains.kotlin.jvm' version '1.8.0' 
  id 'application' 
}

repositories {
  mavenCentral()
}

sourceSets {
  main.kotlin.srcDirs = ['src']
}

compileKotlin {
  kotlinOptions {
    jvmTarget = "17"
  }
}

application {
  mainClass = 'demo.AppKt' 
}

Then in src/ we can put

package demo

class App {}

fun main() {
  println("Hello")
}

Then gradle build run will build and run your application.

You can attempt to reduce the amount of RAM the gradle daemon uses, the thing that makes kotlin compilation not horrifically slow, with export GRADLE_OPTS="-Xmx64m -Dorg.gradle.jvmargs='-Xmx256m -XX:MaxMetaspaceSize=256m'"

&filetype will return something like java or javascript. So this will work

if (&filetype == "java") 
  " whatever you want
endif

There's a src.zip file in /usr/lib/jvm/jdk-17/lib. We can list all the files in this to extract the java imports.

unzip -l src.zip | 
awk '{ print $4 }' | 
sed 's/[^/]*\///'  | 
grep -v module-info | 
grep -v package-info |
sed 's/\.java$//' | 
tail -n +4 | 
sed '/^$/d' | 
sed 's/\//./g'