# Interfaces in Kotlin. Who said interfaces can't have code? (KAD 26)

DevFeed: [Interfaces in Kotlin. Who said interfaces can't have code? (KAD 26)](<https://devfeed.tech/articles/interfaces-in-kotlin-who-said-interfaces-can-t-have-code-kad-26-27173.md>)

Original publisher: [Read original article](<https://antonioleiva.com/interfaces-kotlin>)

Published: 2017-06-06T00:00:00Z

Content type: tutorial

Language: en

Sources: [Antonio Leiva](<https://devfeed.tech/sources/antonio-leiva.md>)

Topics: [interfaces](<https://devfeed.tech/topics/interfaces.md>), [Kotlin](<https://devfeed.tech/topics/kotlin.md>), [Code](<https://devfeed.tech/topics/code.md>), [Inheritance](<https://devfeed.tech/topics/inheritance.md>), [Java](<https://devfeed.tech/topics/java.md>), [Polymorphism](<https://devfeed.tech/topics/polymorphism.md>)

Tags: [code](<https://devfeed.tech/tags/code.md>), [context](<https://devfeed.tech/tags/context.md>), [delegation](<https://devfeed.tech/tags/delegation.md>), [implement](<https://devfeed.tech/tags/implement.md>), [inheritance](<https://devfeed.tech/tags/inheritance.md>), [interfaces](<https://devfeed.tech/tags/interfaces.md>), [java](<https://devfeed.tech/tags/java.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>)

## AI overview

This tutorial explains how Kotlin interfaces can include method implementations, enabling code reuse and composition beyond traditional Java interfaces. It also covers the limitation that interfaces cannot retain state and introduces interface delegation.

## Source excerpt

Everything Android, Kotlin and other random topics