How to implement finalize () in kotlin?

Question

Today I implement Closeable in kotlin, and, as I already did in java in the past, I want to implement finalize() as the last backup tool in case the client code forgets to close it, the critical resource is not recovered. I consider this resource critical enough to add this reserve, despite the unreliability of this reserve. However, kotlin.Any does not declare a finalize method, which means that I cannot just do this:

 class Resource: Closeable { fun close() {} override fun finalize() { close()} } 

This is not good, at least not as good as it should be. Now I will return to simple Java as a workaround. Does anyone know how to do this in pure Kotlin?

PS: My current workaround:

FinalizedCloseable.java:

 public abstract class FinalizedCloseable implement Closeable { @Override protected void finalize() { close(); } } 

Kotlin:

 class Resource: FinalizedCloseable(), Closeable { fun close() {} override fun finalize() { close()} } 

But this workaround requires a superclass. If the next time my other Resource already received a superclass, this workaround will not work without a lot of templates.

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EDIT: now I know how to implement finalize (), but the IDEA kotlin plugin is not smart enough to know that this is a finalizer and thus mark it with some warning. After struggling for a while, I found how to suppress these warnings and want to share it:

 class C { @Suppress("ProtectedInFinal", "Unused") protected fun finalize() {} } 

Answer 1

The official documentation describes this.

To override finalize (), all you have to do is simply declare it without using the override keyword:

 class C { protected fun finalize() { // finalization logic } }