# Top 10 Kotlin Stack Overflow questions, pt 3 - nulls and such

DevFeed: [Top 10 Kotlin Stack Overflow questions, pt 3 - nulls and such](<https://devfeed.tech/articles/top-10-kotlin-stack-overflow-questions-pt-3-nulls-and-such-27091.md>)

Original publisher: [Read original article](<https://zsmb.co/top-10-kotlin-stack-overflow-questions-3/>)

Author: Márton Braun

Published: 2018-05-08T08:00:00Z

Content type: tutorial

Language: en

Sources: [zsmb.co](<https://devfeed.tech/sources/zsmb-co.md>)

Topics: [Kotlin](<https://devfeed.tech/topics/kotlin.md>), [Stack Overflow](<https://devfeed.tech/topics/stackoverflow.md>), [Code](<https://devfeed.tech/topics/code.md>)

Tags: [android](<https://devfeed.tech/tags/android.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>), [marton-braun](<https://devfeed.tech/tags/marton-braun.md>), [null](<https://devfeed.tech/tags/null.md>), [safe-call-operator](<https://devfeed.tech/tags/safe-call-operator.md>), [smart-cast](<https://devfeed.tech/tags/smart-cast.md>), [stack-overflow](<https://devfeed.tech/tags/stack-overflow.md>), [zsmb](<https://devfeed.tech/tags/zsmb.md>), [zsmb-co](<https://devfeed.tech/tags/zsmb-co.md>), [zsmb13](<https://devfeed.tech/tags/zsmb13.md>), [zsmbco](<https://devfeed.tech/tags/zsmbco.md>)

## AI overview

The third and final article in a series explains Kotlin nullability, including why smart casts do not work on mutable properties and how the null assertion operator can cause runtime crashes.

## Source excerpt

The third and final part covers topics of nullability and some small extras to wrap up the series.