# exhaustive

Published articles for exhaustive.

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## Nice and Naughty Cases of Pattern Matching

DevFeed: [Nice and Naughty Cases of Pattern Matching](<https://devfeed.tech/articles/nice-and-naughty-cases-of-pattern-matching-23025.md>)

Original publisher: [Read original article](<https://www.javaadvent.com/2025/12/nice-and-naughty-cases-of-pattern-matching.html>)

Author: Cay Horstmann

Published: 2025-12-08T02:02:26Z

Content type: article

Language: en

Sources: [Java Advent Calendar](<https://devfeed.tech/sources/java-advent-calendar.md>)

Topics: [Java](<https://devfeed.tech/topics/java.md>), [Programming](<https://devfeed.tech/topics/programming.md>), [Code](<https://devfeed.tech/topics/code.md>)

Tags: [2025](<https://devfeed.tech/tags/2025.md>), [article](<https://devfeed.tech/tags/article.md>), [enums](<https://devfeed.tech/tags/enums.md>), [exhaustive](<https://devfeed.tech/tags/exhaustive.md>), [expression](<https://devfeed.tech/tags/expression.md>), [interfaces](<https://devfeed.tech/tags/interfaces.md>), [java](<https://devfeed.tech/tags/java.md>), [java-language](<https://devfeed.tech/tags/java-language.md>), [pattern-matching](<https://devfeed.tech/tags/pattern-matching.md>), [patterns](<https://devfeed.tech/tags/patterns.md>), [programming](<https://devfeed.tech/tags/programming.md>), [sealed](<https://devfeed.tech/tags/sealed.md>), [statement](<https://devfeed.tech/tags/statement.md>), [syntax](<https://devfeed.tech/tags/syntax.md>), [types](<https://devfeed.tech/tags/types.md>)

### AI overview

This article examines Java pattern matching in switch and instanceof, explaining when it fits data-oriented programming, when it becomes an antipattern, and how it interacts with legacy behavior. It uses sealed interfaces, records, enums, and JSON values to illustrate exhaustive pattern matching.

### Source excerpt

Since Java 14, the Java switch and instanceof statements have been enhanced, in multiple phases, to support pattern matching and a "data-oriented" programming style. In this article, I explore when this programming style is beneficial, and why. I look at the sweet spot of perfect pattern usage, absolute antipatterns where it should not be used, [...] The post Nice and Naughty Cases of Pattern Matching appeared first on JVM Advent.

## Automating Exhaustive Branch Coverage for Sealed Types in Kotlin

DevFeed: [Automating Exhaustive Branch Coverage for Sealed Types in Kotlin](<https://devfeed.tech/articles/automating-exhaustive-branch-coverage-for-sealed-types-in-kotlin-20458.md>)

Original publisher: [Read original article](<https://eng.wealthfront.com/2025/11/20/sealed-tests/>)

Author: Sean Amos

Published: 2025-11-20T16:33:33Z

Content type: tutorial

Language: en

Sources: [Wealthfront](<https://devfeed.tech/sources/wealthfront.md>)

Topics: [Kotlin](<https://devfeed.tech/topics/kotlin.md>), [Testing](<https://devfeed.tech/topics/testing.md>), [Unit testing](<https://devfeed.tech/topics/unit-testing.md>), [test-coverage](<https://devfeed.tech/topics/test-coverage.md>), [Code quality](<https://devfeed.tech/topics/code-quality.md>)

Tags: [android](<https://devfeed.tech/tags/android.md>), [automation](<https://devfeed.tech/tags/automation.md>), [code](<https://devfeed.tech/tags/code.md>), [code-quality](<https://devfeed.tech/tags/code-quality.md>), [exhaustive](<https://devfeed.tech/tags/exhaustive.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>), [sealed](<https://devfeed.tech/tags/sealed.md>), [sealed-classes](<https://devfeed.tech/tags/sealed-classes.md>), [subtype](<https://devfeed.tech/tags/subtype.md>), [test-coverage](<https://devfeed.tech/tags/test-coverage.md>), [testing](<https://devfeed.tech/tags/testing.md>), [unit-testing](<https://devfeed.tech/tags/unit-testing.md>), [wealthfront-engineering](<https://devfeed.tech/tags/wealthfront-engineering.md>)

### AI overview

This article explains how to build an Exhaustive Test Runner for Kotlin sealed classes and interfaces. The approach ensures that functions accepting sealed parameters have at least one unit test for each subtype, including future subtypes added to the hierarchy.

### Source excerpt

We take code correctness and code quality seriously at Wealthfront. One of the most effective ways we ensure that our code is correct is through rigorous unit testing and strong typing. In Kotlin, sealed classes and sealed interfaces offer a powerful tool to model restricted class hierarchies. They provide strong guarantees about the types in... Read more

## Sealed Types

DevFeed: [Sealed Types](<https://devfeed.tech/articles/sealed-types-25064.md>)

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

Author: author@typealias.com (Dave Leeds)

Published: 2024-01-16T00:00:00Z

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>), [interfaces](<https://devfeed.tech/topics/interfaces.md>)

Tags: [classes](<https://devfeed.tech/tags/classes.md>), [enum](<https://devfeed.tech/tags/enum.md>), [exhaustive](<https://devfeed.tech/tags/exhaustive.md>), [exhaustive-matching](<https://devfeed.tech/tags/exhaustive-matching.md>), [interfaces](<https://devfeed.tech/tags/interfaces.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>), [programming](<https://devfeed.tech/tags/programming.md>), [sealed](<https://devfeed.tech/tags/sealed.md>), [sealed-class](<https://devfeed.tech/tags/sealed-class.md>), [sealed-interface](<https://devfeed.tech/tags/sealed-interface.md>), [subtype](<https://devfeed.tech/tags/subtype.md>), [types](<https://devfeed.tech/tags/types.md>), [when-conditional](<https://devfeed.tech/tags/when-conditional.md>), [when-expression](<https://devfeed.tech/tags/when-expression.md>)

### AI overview

A tutorial chapter explains how Kotlin sealed interfaces and classes restrict the set of possible types, helping ensure that all possibilities are handled in a when expression.

### Source excerpt

In Chapter 5, we saw how limiting our options can be a good thing. In that chapter, we used enum classes to limit our values, which allows Kotlin to ensure that we account for all possibilities in a when expression. We can get a similar benefit for our types by using sealed interfaces and classes. In this chapter, we'll visit Cecil's Ice Shop to learn all about sealed types. Let's get started!