# Safe-Call Operator

Published articles for Safe-Call Operator.

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## KotlinConf 2025 Announcements

DevFeed: [KotlinConf 2025 Announcements](<https://devfeed.tech/articles/kotlinconf-2025-announcements-39349.md>)

Original publisher: [Read original article](<https://kt.academy/article/kotlinconf2025-announcements>)

Published: 2025-06-03T00:00:00Z

Content type: article

Language: en

Sources: [Kt. Academy](<https://devfeed.tech/sources/kt-academy.md>)

Topics: [Kotlin](<https://devfeed.tech/topics/kotlin.md>), [destructuring](<https://devfeed.tech/topics/destructuring.md>), [exceptions](<https://devfeed.tech/topics/exceptions.md>), [union types](<https://devfeed.tech/topics/union-types.md>), [syntax](<https://devfeed.tech/topics/syntax.md>), [Safe-Call Operator](<https://devfeed.tech/topics/safe-call-operator.md>)

Tags: [announcements](<https://devfeed.tech/tags/announcements.md>), [destructuring](<https://devfeed.tech/tags/destructuring.md>), [exceptions](<https://devfeed.tech/tags/exceptions.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>), [kotlinconf](<https://devfeed.tech/tags/kotlinconf.md>), [new-features](<https://devfeed.tech/tags/new-features.md>), [safe-call-operator](<https://devfeed.tech/tags/safe-call-operator.md>), [syntax](<https://devfeed.tech/tags/syntax.md>), [union-types](<https://devfeed.tech/tags/union-types.md>), [workshop-learning-programming](<https://devfeed.tech/tags/workshop-learning-programming.md>)

### AI overview

The article summarizes announcements from KotlinConf 2025, including K2 becoming stable, upcoming name-based destructuring, and rich errors with language-level support for result-or-error types and related operators.

### Source excerpt

The greatest announcements from KotlinConf 2025.

## Nulls and Null Safety

DevFeed: [Nulls and Null Safety](<https://devfeed.tech/articles/nulls-and-null-safety-25061.md>)

Original publisher: [Read original article](<https://typealias.com/start/kotlin-nulls/>)

Author: author@typealias.com (Dave Leeds)

Published: 2021-03-30T00:00:00Z

Content type: tutorial

Language: en

Sources: [Dave Leeds on Kotlin - typealias.com](<https://devfeed.tech/sources/dave-leeds-on-kotlin-typealias-com.md>)

Topics: [Kotlin](<https://devfeed.tech/topics/kotlin.md>), [Jetpack Compose](<https://devfeed.tech/topics/jetpack-compose.md>)

Tags: [elvis-operator](<https://devfeed.tech/tags/elvis-operator.md>), [introduction](<https://devfeed.tech/tags/introduction.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>), [learn-to-program](<https://devfeed.tech/tags/learn-to-program.md>), [not-null-assertion-operator](<https://devfeed.tech/tags/not-null-assertion-operator.md>), [null](<https://devfeed.tech/tags/null.md>), [null-safety](<https://devfeed.tech/tags/null-safety.md>), [optional](<https://devfeed.tech/tags/optional.md>), [programming](<https://devfeed.tech/tags/programming.md>), [safe-call-operator](<https://devfeed.tech/tags/safe-call-operator.md>), [smart-cast](<https://devfeed.tech/tags/smart-cast.md>)

### AI overview

An introduction to nulls and null safety in Kotlin, explaining that variables may not always hold a value and setting up a coffee-rating example implemented in Kotlin.

### Source excerpt

So far in this book, every time that we created a variable, whether it was a String, an Int, or a Boolean, we assigned a value to it. There are times, though, when we need to create a variable that might not actually hold a value! This brings us to the exciting topic of nulls! Introduction to Nulls James has set up a coffee stand downtown, and he's ready to start sharing his fine brew!

## 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.

## Choosing between with() and run()

DevFeed: [Choosing between with() and run()](<https://devfeed.tech/articles/choosing-between-with-and-run-25032.md>)

Original publisher: [Read original article](<https://typealias.com/guides/choosing-between-with-and-run/>)

Author: author@typealias.com (Dave Leeds)

Published: 2017-09-14T01:23:30Z

Content type: tutorial

Language: en

Sources: [Dave Leeds on Kotlin - typealias.com](<https://devfeed.tech/sources/dave-leeds-on-kotlin-typealias-com.md>)

Topics: [Kotlin](<https://devfeed.tech/topics/kotlin.md>), [Library](<https://devfeed.tech/topics/library.md>), [Code](<https://devfeed.tech/topics/code.md>), [context](<https://devfeed.tech/topics/context.md>)

Tags: [comparison](<https://devfeed.tech/tags/comparison.md>), [extension-function](<https://devfeed.tech/tags/extension-function.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>), [programming](<https://devfeed.tech/tags/programming.md>), [readability](<https://devfeed.tech/tags/readability.md>), [run](<https://devfeed.tech/tags/run.md>), [safe-call-operator](<https://devfeed.tech/tags/safe-call-operator.md>), [scope-functions](<https://devfeed.tech/tags/scope-functions.md>), [standard-library](<https://devfeed.tech/tags/standard-library.md>)

### AI overview

This Kotlin tutorial compares with() and run(), explaining that they are nearly identical in compiled behavior and differ mainly in syntax. It highlights the extension-function advantage of safe-call handling for nullable receivers and discusses readability trade-offs.

### Source excerpt

In Kotlin's standard library, the Standard.kt file contains a number of scope functions that put a receiver object into a new scope as either this or as an argument (e.g., it). The with() function tends to be a bit of an outlier. The others are all extension functions, so they're invoked on an object. with(), on the other hand, takes its receiver (the object that it's operating upon) as an argument.

## Java Optionals and Kotlin Nulls

DevFeed: [Java Optionals and Kotlin Nulls](<https://devfeed.tech/articles/java-optionals-and-kotlin-nulls-25040.md>)

Original publisher: [Read original article](<https://typealias.com/guides/java-optionals-and-kotlin-nulls/>)

Author: author@typealias.com (Dave Leeds)

Published: 2017-09-01T00:00:00Z

Content type: tutorial

Language: en

Sources: [Dave Leeds on Kotlin - typealias.com](<https://devfeed.tech/sources/dave-leeds-on-kotlin-typealias-com.md>)

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

Tags: [exception](<https://devfeed.tech/tags/exception.md>), [extension-function](<https://devfeed.tech/tags/extension-function.md>), [filter](<https://devfeed.tech/tags/filter.md>), [java](<https://devfeed.tech/tags/java.md>), [java-8](<https://devfeed.tech/tags/java-8.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>), [migration-guide](<https://devfeed.tech/tags/migration-guide.md>), [null](<https://devfeed.tech/tags/null.md>), [null-safety](<https://devfeed.tech/tags/null-safety.md>), [optional](<https://devfeed.tech/tags/optional.md>), [programming](<https://devfeed.tech/tags/programming.md>), [safe-call-operator](<https://devfeed.tech/tags/safe-call-operator.md>), [standard-library](<https://devfeed.tech/tags/standard-library.md>), [transformation](<https://devfeed.tech/tags/transformation.md>)

### AI overview

A guide to translating Java Optional usage into idiomatic Kotlin null-safety patterns. It compares creation, transformation, filtering, and conditional operations, while noting trade-offs and cases where Kotlin nullable types replace Optional.

### Source excerpt

When Java 8 introduced Streams for operating on collections of data, it also introduced a similar concept, Optional, which has many methods that are similar to Stream, but operates on a single value that might or might not be present. As you migrate your projects from Java to Kotlin, you might come across some Optional objects. What should you do? Should you leave them as Optional, or change them to more idiomatic Kotlin?