Kotlin script engine with spring boot self-running war

1

I’m trying to write kotlin view engine for Spring MVC. I’m write custom ViewResolver and View, spring successfully calls them. In view I want to start Kotlin Script Engine:

class KotlinView constructor(path: String) : View {
    ...
    override fun render(model: MutableMap<String, *>?, request: HttpServletRequest, response: HttpServletResponse) {
        val classLoader = Thread.currentThread().getContextClassLoader();
        val compilableEngine = ScriptEngineManager(classLoader).getEngineByName("kotlin") as Compilable
        ...
    }
}

If I run app from IDEA, it works fine (Debug configuration - Gradle with bootRun gradle task). So, no problem here.

But if I run from java -jar /path/to/my/app.war, expression ScriptEngineManager(classLoader).getEngineByName("kotlin") returns null, and kotlin exception occurs because cannot cast null to Compilable.

In my build.gradle.kts I added this:

tasks.withType<BootWar> {
    requiresUnpack("**/kotlin-*.jar")
    requiresUnpack("**/kotlinx-*.jar")
}

Link

These files are marked with comment in war, and appears in my user temporary folder when app started via java -jar ....

I’m trying with kotlin-compiler and kotlin-scripting-jsr223-embeddable, behaviour is same.

I think that is about ClassLoaderProblems, but I can’t understand what went wrong. How to help ScriptEngineManager to find KotlinEngine in temporary folder? Or another solution?

UPD. I created repository with example. See KotlinView class, all requests are being processed with this class for now.

PS. My stackoverflow question