JDK 9 alternatives and similar libraries

Based on the "JVM and JDK" category.

OpenJ9

8.0 10.0 JDK 9 VS OpenJ9

Eclipse OpenJ9: A Java Virtual Machine for OpenJDK that's optimized for small footprint, fast start-up, and high throughput. Builds on Eclipse OMR (https://github.com/eclipse/omr) and combines with the Extensions for OpenJDK for OpenJ9 repo.
Avian

6.2 0.0 L1 JDK 9 VS Avian

[INACTIVE] Avian is a lightweight virtual machine and class library designed to provide a useful subset of Java's features, suitable for building self-contained applications.

Collect, organize, and act on massive volumes of high-resolution data to power real-time intelligent systems.

Promo influxdata.com

ParparVM

1.8 - JDK 9 VS ParparVM

VM with non-blocking concurrent GC for iOS.
OpenJDK

- JDK 9 VS OpenJDK

Open-source implementation for Linux.
Zulu OpenJDK 9

- JDK 9 VS Zulu OpenJDK 9

Early access OpenJDK 9 builds for Windows, Linux, and Mac OS X.
Zulu OpenJDK

- JDK 9 VS Zulu OpenJDK

OpenJDK builds for Windows, Linux, and Mac OS X through Java 8.