OpenJ9
A Java Virtual Machine for OpenJDK
... Virtual Machine. "Independent implementation" means it was built using the Java Virtual Machine specification without using any code from any other Java Virtual Machine. The OpenJ9 JVM combines with the Java Class libraries from OpenJDK to create a complete JDK tuned for footprint, performance, and reliability that is well suited for cloud deployments. The original source contribution to OpenJ9 came from the IBM "J9" JVM which has been used in production by thousands of Java applications.