Lothar Schulz

Java Sealed Classes vs. Kotlin Sealed Classes #Slideless

What if you never had to write another null check for an API response? See how sealed classes in Java and Kotlin make it possible.

Java Sealed Classes vs. Kotlin Sealed Classes #Slideless
#1about 2 minutes

Introducing sealed classes in Java 17

Sealed classes restrict which other classes may extend them, giving developers more control over inheritance hierarchies.

#2about 1 minute

Understanding Kotlin sealed classes as super enums

Kotlin's sealed classes act like enums that can hold state, making them powerful containers for different types of data.

#3about 13 minutes

Refactoring Kotlin code to eliminate nulls with sealed classes

A live coding demo shows how to replace nullable return types with a sealed class to explicitly handle success and failure cases.

#4about 11 minutes

Implementing sealed classes in Java to handle API results

This live coding example demonstrates creating a Java sealed class with final subclasses to manage success and failure states from an API call.

#5about 3 minutes

Using Java sealed interfaces with records for conciseness

Code is refactored from sealed classes to sealed interfaces implemented by records, significantly reducing boilerplate code.

#6about 3 minutes

Applying pattern matching in Java with switch expressions

The if-instanceof chain is replaced with a modern switch expression for exhaustive and more readable pattern matching.

#7about 3 minutes

Conclusion on Java vs Kotlin sealed class parity

Sealed classes in both Java and Kotlin are now functionally on par, so language choice can be based on other factors.

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