Java Predictions for 2021 on Foojay

Geertjan Wielenga has posted "Java Predictions for 2021" on Foojay Today. It is a collection of predictions about Java in 2021 from eight members of the Java community (Almas Baimagambetov, Stephen Chin, Brice Dutheil, Marcus Hirt, Reza Rahman, Matt Raible, Simon Ritter, and me). The predictions are concisely written and it's interesting to see the overlap between them while at the same time seeing how different parts of "Java" are important to different people. In this post, I elaborate a bit more on my predictions that were included in "Java Predictions for 2021".

I provided two somewhat related predictions for Java in 2021:

• "Records will likely be finalized in 2021 and will be widely popular with Java developers who are fortunate enough to work on a version of the JDK with final (not preview) Record support.
• The release of the OpenJDK 17 implementation in 2021 (which will be the foundation of Oracle's LTS version and other community members' LTS versions) will motivate many who are already working on versions of the JDK later than JDK 8 to start moving or investigate moving to JDK 17. However, JDK 8 will remain widely popular (probably will still be used by over half of Java developers), creating (in the long term) a bimodal distribution of most commonly used JDK versions (8 and 17)."

Java Records Final in 2021

The prediction that Java Records will be final in 2021 is not a risky one. Records have a been a "preview" feature in JDK 14 (JEP 359) and JDK 15 (JEP 384) and now JEP 395 "proposes to finalize the feature in JDK 16" (which is currently in Rampdown Phase One and is scheduled to be released for General Availability in March 2021). Because Records have been through two preview releases already, it seems unlikely that they won't be final as of JDK 16. In the event that they do need one more release, JDK 17 should be released in October 2021.

And Then There Were Two: JDK 8 and JDK 17

2021 will see the beginning of a move to a bimodial distribution of JDK releases most commnoly used. With JDK 17's likely release in October 2021, we'll likely see many Java shops that have already migrated to a version of JDK later than JDK 8 move to that newly released JDK 17. There have been some nice additions and improvements to OpenJDK (which is the foundation of several different JDK implementations) that have been added in recent versions of the JDK and JDK 17 will be an "LTS" (Long-term Support) release for many of the JDK implementations. As an "LTS" release, JDK 17 will appeal to Java shops that want to only be on versions with long-term support and JDK 17 will be the first since JDK 11 to have this status for many of the JDK implementations.

JDK 8 appears to still be the most widely used release of the Java even in 2020. There are several metrics and andecdotal evidence that suggest this. One example is the JetBrains 2020 Development Ecosystem survey that suggests that 75% of Java developers responding to the survey use JDK 8 (some of these developers use other versions of JDK as well) and the same chart shows 32% of responding Java developers use JDK 11. For reference, the 2019 and 2018 versions of this same survey indicated that 83% and 84% of Java developers used JDK 8 in 2019 and 2018 respectively.

JDK 8 is a version with long-term support (Oracle, for example, offers "extended support" for JDK 8 through December 2030) in several JDK implementations and some shops appear hesitant to move to JDK 9 with its introduced modularity support (and need for libraries and frameworks to support that as well). For those shops that have already migrated to a version of JDK later than JDK 8, it should be relatively easier to migrate to JDK 17. I think that some JDK 8 shops will be motivated to make the "big move" and, while doing that, will jump directly to JDK 17. However, I expect that we'll still see at least half of JDK developers still using JDK 8 even at the end of 2021. For the half of JDK users already using a version later than JDK 8 (not counting users of version of JDK before JDK 8), I think we'll begin to see them migrate to JDK 17 in 2021 and the following year or two. Within the next year or two, I expect most JDK developers will be working with JDK 8 or JDK 17.

There will, of course, be some small pockets of JDK developers using other versions before JDK 8, between JDK 8 and JDK 17 (perhaps because they use a feature or garbage collector no longer available in JDK 17), and newer versions of JDK as they are released in 2022.

"LTS" Among JDK Providers

The following are some roadmaps of various JDK vendors' JDK implementations that provide insight into each vendor's LTS concept. Although "LTS" often is referring to Oracle's plan regarding their JDK implementation built on top of OpenJDK, other JDK vendors have generally treated these "LTS" releases in similar manner.

• AdoptOpenJDK Support and Release Roadmap
  • Shows "Java 17" as LTS.
  • States, "In addition, every three years one feature release will be designated as a Long Term Supported (LTS) release. We will produce LTS releases for at least four years."
  • States, "As a general philosophy, AdoptOpenJDK will continue to build binaries for LTS releases as long as the corresponding upstream source is actively maintained."
• Oracle Java SE Support Roadmap
  • States, "For product releases after Java SE 8, Oracle will designate a release, every three years, as a Long-Term-Support (LTS) release. Java SE 11 is an LTS release."
• Azul Java Support Roadmap
  • References Long Term Support (LTS) and Medium Term Support (MTS) and states, "Releases designated as LTS are those same LTS releases as designated by Oracle and the OpenJDK community."
• Amazon Corretto
  • "Amazon Corretto 8 & 11 support extended" states, "Amazon is extending long-term support (LTS) for Amazon Corretto 8 from June 2023 to May 2026 and for Amazon Corretto 11 from August 2024 to September 2027. Long-term support (LTS) for Corretto includes security updates and specific performance enhancements released at least quarterly."

Looking Forward to 2021

Most of us are hoping for a better year in 2021 than we've experienced in 2020. The finalization of Java Records and General Availability of JDK 17 in 2021 are going to be significant positive events for Java developers and I'm hoping that these will only be a small representative sample of positive events and advancements that benefit a much wider population in 2021.