What Is Eclipse OpenJ9

This section provides a quick introduction of Eclipse OpenJ9, which is an independent implementation of a JVM (Java Virtual Machine) developed by the Eclipse Foundation.

What Is Eclipse OpenJ9? - Eclipse OpenJ9 is an independent implementation of a JVM (Java Virtual Machine) developed by the Eclipse Foundation. It was built using the JVM specification without using any code from any other JVM implementations.

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 for the last two decades. In September 2017, IBM completed open sourcing the J9 JVM as "Eclipse OpenJ9" at the Eclipse Foundation.

According to eclipse.org/openj9 Website, using the combination of OpenJDK 8 and OpenJ9 demonstrates significantly better performance than the combination of Oracle JDK and HotSpot as presented below:

Performance Comparison of OpenJ9 vs. HotSpot
Performance Comparison of OpenJ9 vs. HotSpot

Table of Contents

 About This Book

 JVM (Java Virtual Machine) Specification

 Java HotSpot VM - JVM by Oracle/Sun

 java.lang.Runtime Class - The JVM Instance

 java.lang.System Class - The Operating System

 ClassLoader Class - Class Loaders

 Class Class - Class Reflections

 JVM Runtime Data Areas

 JVM Stack, Frame and Stack Overflow

 Thread Testing Program and Result

 CPU Impact of Multi-Thread Applications

 I/O Impact of Multi-Thread Applications

 CDS (Class Data Sharing)

 Micro Benchmark Runner and JVM Options

 Micro Benchmark Tests on "int" Operations

 Micro Benchmark Tests on "long" Operations

 Micro Benchmark Tests in JIT Compilation Mode

 Micro Benchmark Tests on "float" and "double" Operations

OpenJ9 by Eclipse Foundation

What Is Eclipse OpenJ9

 Install OpenJ9 JVM with OpenJDK on CentOS Systems

 Footprint Comparison - OpenJ9 vs. HotSpot

 Startup Time Comparison - OpenJ9 vs. HotSpot

 JRockit JVM 28.2.7 by Oracle Corporation

 Outdated Tutorials

 References

 Full Version in PDF/EPUB