.NET

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.

Eclipse OpenJ9

eclipse-openj9/openj9

Low-footprint JVM from IBM (in Semeru runtimes) tuned for fast startup and dense containers.

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Original cross-platform .NET implementation, now handed to WineHQ; superseded by modern .NET.