“Java 9 is much bigger than Jigsaw”
Java 9 is more than just Project Jigsaw. We talked with Monica Beckwith, JavaOne Rock Star and JAX London speaker about her favorite improvements in the upcoming Java 9, Project Jigsaw and the biggest misconceptions about the upcoming release.
JAXenter: Georges Saab, chairperson of the OpenJDK governing board and vice president of development for the Java Platform Group at Oracle told us in early June that many developers will probably get started on JDK 9 without modules. How do you feel about the modular ecosystem?
Monica Beckwith: For the long term, it’s a great boost to the Java Runtime Environment and hence the Java ecosystem. Imagine being able to build your application and its runtime environment in a modular format. Then, your customer can deploy it right off the bat without having to worry about the JDK version or the footprint.
JAXenter: What’s the difference in the performance of contended locks between JDK 8 and 9?
Monica Beckwith: If you are looking for pure numbers, then the impact varies based on the amount of contention. The simplest way to think of it is that prior to JDK 9, all inflated locks (the ones that wouldn’t get optimized away) would take a slow path. The contended lock optimization introduced in JDK 9 introduces a few fast path optimizations for frequent code paths. So, you would find things like optimized notify path that would transfer threads in the wait queue directly to the entry queue and optimized entry for inflated locks.
JAXenter: There will definitely be Java 9 features that pose a challenge to developers but is Jigsaw one of them? What features, if any, do you find particularly challenging?
Monica Beckwith: I think with Jigsaw getting its much-needed support from the IDEs, people would feel less threatened by the changes and would eventually welcome it.
JAXenter: Even though Mark Reinhold said at the last JavaOne keynote that Java 9 is much bigger than Jigsaw, this feature is undoubtedly the star of the release. But what about those other JEPs? Which one do you like best?
Monica Beckwith: I think String density is a winner here. My favorite may be the contended locking improvements because that’s the first of its kind. But the String density improvements are the biggest that any release has yet seen. The impact will be felt by almost every user.
SEE MORE: Java 9 modules – JPMS basics
JAXenter: What is the most important misconception about Java 9? How about Jigsaw?
Monica Beckwith: The number one misconception is that Java 9 is a Jigsaw release. Nope. It’s not true: Java 9 is much bigger than that. Actually, I am currently writing a book on Java 9. There’s so much in this new release, like its performance, the logging interface, the new microbenchmarking harness that’s now a part of the JDK, the fact that the default collector in Java 9 is G1 GC, reactive programming, JShell, VarHandles, segmented code cache, so many things…
The number one misconception about Jigsaw is that it will break everything :)
JAXenter: What would you like to see in Java 10?
Monica Beckwith: I am most excited about Project Valhalla and the enhancements that it will bring to the Java VM.
JAXenter: What will attendees get out of your talk?
Monica Beckwith: Attendees will learn about locking optimizations in Java. I will also introduce an awesome tool called Oracle Developer Studio Performance Analyzer and work through the analysis of finding out the improvements in contended locking. Also, I will be comparing the changes in Java 9 to Java 8.
look what you made me do
Interested in learning more about Java? Monica Beckwith will be at JAX London on October 10, 2017. Her talk, “Java 9: Beyond Contention!”, is a part of the Java Core & Languages track, which contains fourteen sessions and one workshop. The goal of this track is to help you enhance your skills — whether it’s about learning new tricks, designing an open source library in Java 8 or rediscovering the joy of being a software engineer. Join us at JAX London!
To find out more about Java 9 and modularity, download the latest issue of JAX Magazine:
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