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JVMLS 2015 - Flexible Types in Kotlin

Java

276K subscribers • 13 videos on Hallway

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  • Recommended by 4 people: 4 in engineering communities.
  • A classic. People kept recommending it from 2015 to 2022.
  • Presented by Andrey Breslav, Kotlin Lead Designer

Advanced. Deep dive for people who know the field.

6.1K views11 years ago4 recommendations

Programming languagesKotlinLanguage design and type systemsJava and the JVM

Andrey Breslav explains how Kotlin handles nullability and type safety when interoperating with Java using flexible types.

JVMLS 2015 - Flexible Types of Kotlin - Andrey Breslav The JVM Language Summit is an open technical collaboration among language designers, compiler writers, tool builders, runtime engineers, and VM architects. In 2015, it convened at Oracle's Santa Clara, CA campus on August 10-12.

Why it's here

4 people recommend this

What people say. Recommended as the definitive explanation of Kotlin's platform and flexible types for Java interoperability.

u/abreslavin r/Kotlin • Recommends

On “What's the meaning of this return type with the two dots (..) when calling Java code from Kotlin?”

Looks like a bug in the IDE, it should not show you these. But if you are curious, it’s called a flexible type, see this talk: link to this video
13View on Reddit

u/crate_crowin r/Kotlin • Recommends

Dynamic types in Kotlin
12View on Reddit

u/abreslavKotlin lead designerin r/Kotlin • Recommends

On “Why is ArrayList a MutableCollection”

Some info is available here: https://kotlinlang.org/docs/reference/java-interop.html#mapped-types These talks have some relevant info: link to this video link to this video
9View on Reddit

u/nhaarmanin r/Kotlin • Recommends

On “NullPointerException in Kotlin”

It doesn't work: link to this video
4View on Reddit

u/hastebrotin r/Kotlin • Recommends

On “What does the ! mean”

>T! means “T or T?” Yepp, that's right. I also wondered what this might mean, when I first encountered it in IntelliJ IDEA. Andrey gave a talk 1 about "platform types" (aka. flexible types) in August, where he explains them in great detail. 1 link to this video (42 mins)
1View on Reddit