# Kotlin: The Problem with \`null\`

DevFeed: [Kotlin: The Problem with \`null\`](<https://devfeed.tech/articles/kotlin-the-problem-with-null-29361.md>)

Original publisher: [Read original article](<https://arturdryomov.dev/posts/kotlin-the-problem-with-null/>)

Author: Artur Dryomov

Published: 2018-01-10T00:00:00Z

Content type: opinion

Language: en

Sources: [Artur Dryomov](<https://devfeed.tech/sources/artur-dryomov.md>)

Topics: [Kotlin](<https://devfeed.tech/topics/kotlin.md>), [RxJava](<https://devfeed.tech/topics/rxjava.md>), [Java](<https://devfeed.tech/topics/java.md>), [jetbrains](<https://devfeed.tech/topics/jetbrains.md>)

Tags: [bytecode](<https://devfeed.tech/tags/bytecode.md>), [errors](<https://devfeed.tech/tags/errors.md>), [java](<https://devfeed.tech/tags/java.md>), [jetbrains](<https://devfeed.tech/tags/jetbrains.md>), [jvm](<https://devfeed.tech/tags/jvm.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>), [null-safety](<https://devfeed.tech/tags/null-safety.md>), [rxjava](<https://devfeed.tech/tags/rxjava.md>), [time](<https://devfeed.tech/tags/time.md>)

## AI overview

The article examines Kotlin's null-safety guarantees and explains why Java interoperability can still allow runtime null-related crashes. Using an RxJava example, it argues that missing nullability metadata in Java bytecode prevents Kotlin's IDE and compiler from detecting the problem, while annotations can expose it during development.

## Source excerpt

I think almost everybody in the CS world knows about the Null References: The Billion Dollar Mistake talk. However, it does not really matter if the concept of null references a good idea or a really bad one. We live in the world where we just have to deal with null this way or another. Yep, just deal with it. So let's ask the "How" question instead of the "Why" one.