Eclipse OpenJ9

.NET

dotnet/runtime

Popular

Microsoft's open-source, cross-platform runtime and SDK for C# and F#; yearly November releases.

Eclipse Temurin

adoptium.net

Popular

Adoptium's free, TCK-certified OpenJDK builds; the most widely used vendor-neutral JDK.

GraalVM

oracle/graal

High-performance JDK with ahead-of-time native-image compilation and polyglot language support.

Amazon Corretto

aws.amazon.com

Amazon's free, long-term-supported OpenJDK distribution used across AWS.

Kotlin Multiplatform

kotlinlang.org

Trending

JetBrains technology for sharing Kotlin business logic, and optionally UI, across Android, iOS, desktop and web.

Mono

mono/mono

Legacy

Original cross-platform .NET implementation, now handed to WineHQ; superseded by modern .NET.