Why is this an issue?

Enabling runFinalizersOnExit is unsafe as it might result in erratic behavior and deadlocks on application exit.

Indeed, finalizers might be force-called on live objects while other threads are concurrently manipulating them.

Instead, if you want to execute something when the virtual machine begins its shutdown sequence, you should attach a shutdown hook.

Noncompliant code example

fun main() {
  System.runFinalizersOnExit(true)  // Noncompliant
}

Compliant solution

fun main() {
    Runtime.getRuntime().addShutdownHook(object : Thread() {
        override fun run() {
            doSomething()
        }
    })
}

Resources

• CERT, MET12-J. - Do not use finalizers. Although this resource talks about Java, the underlying information concerning the JVM are just as relevant for Kotlin.