Saturday, May 29, 2021

Chasing Java's release train, from 8 to 16. Part 2: The race to the next LTS release.

In the first part we thoroughly went through the massive amount of features delivered in scope of JDK-9. Nevertheless, this release was always considered as being transitional, with little or no adoption expected. It has a mission to kick off the race towards next LTS release, JDK-11.

JDK 10

JDK-10, the first release followed the six months cadence cycle, brought a number of new features into the language and JVM itself. Let us take a look at the most interesting ones from the developer's perspective.

Undoubtedly, JDK-10 release has quite moderate amount of features comparing to JDK-9, but every one of those was delivered much faster, thanks to the new release cycle.

JDK 11

The first LTS release of the JDK following the new schedule, JDK-11, had seen the light in 2018, six month after JDK-10 release. It finally brought a long awaited stability and established a new baseline in post JDK-9 world. It also included a number of features.

It worth to note that JDK-11 had introduced two new garbage collectors, ZGC and Epsilon, both were marked as experimental. We are going to get back to those in the upcoming posts while discussing more recent JDK releases.

So, where are we today? The JDK-11 slowly but steadily getting more adoption as more and more projects migrate off the JDK-8. Nonetheless, the majority are still on JDK-8 and in my opinion, there are no reasons to expect drastic changes of the balance within next couple of years. But this is another story ...

Wednesday, March 31, 2021

Chasing Java's release train, from 8 to 16. Part 1: JDK 9, the last big banger ...

A lot has been said about JDK's new 6 months release cadence cycle, and arguably, this is one of the most profound decisions being made in the recent history of the language and JVM platform in general. But if you, like me and other ~60% of the Java developers out there, stuck with JDK 8, the new releases mean little to your day to day job. But the language changes, the standard library changes, the JVM changes and so does the tooling around it. More importantly, the ecosystem also changes by aggressively raising the compatibility baselines. Java in 2021 is not the same as it was in 2020, 2017 and all the more in 2014, when Java 8 has seen the light. The soon to be out JDK 17, the next LTS release, would raise the bar even higher.

So the challenge many of us, seasoned Java developers, are facing is how to stay up to date? The risk of your skills becoming outdated is real. Hence this series of the blog posts: to consolidate the changes in the language, JVM, standard library and tooling over each release, primary from the perspective of the developer. At the end, we should be all set to meet the JDK 17 fully armed. To mention upfront, we are not going to talk about incubating or preview features, nor about come-and-go ones (looking at you, jaotc). Whenever it makes sense, the feature would have a corresponding JEP link, but overall there are many changes not covered by dedicated proposals. I will try to include as much as possible but there are chances some useful features may still slip away.

With that, let us open the stage with JDK 8.


Unsurprisingly, JDK 8 does not only receive the security patches and bugfixes but gets some of the new features from the upstream. The two notable ones are:
  • Improved Docker container detection and resource configuration usage: since 8u191, the JVM is fully container-aware (see please JDK-8146115). The support is only available on Linux based platforms and enabled by default.

  • JFR backport: since 8u262, JFR is supported seamlessly (see please JDK-8223147), no need to pass -XX:+UnlockCommercialFeatures and alike anymore

Although not strictly related, thanks to the JFR backport, the latest JDK Mission Control 8 release comes very handy to everyone. Hopefully, your organization does update to the recent JDK patch releases on the regular basis and these features are already available to you.


The JDK 9 release was just huge (90+ JEPs): not only from the perspective of the bundled features, but also from the impact on the platform and ecosystem. It was 2017 but even today the groundwork established by JDK 9 still continues. Let us take a look at the major features which went into it.

The JDK 9 changeset was massive, at the same time - this is the last big bang release. We have covered most interesting pieces of it, at least from the developer's point of view. In the upcoming posts we are going to dissect other releases, one by one, and reveal the hidden gems of each.