Upgrading from Java 8 to Java 12

Mike's Notes

Notes on Java remaining open.

• The most precise explanations I've heard.
• Develop on Java 12 OpenJDK.

Resources

• https://www.infoq.com/articles/upgrading-java-8-to-12
• https://www.infoq.com/presentations/panel-java-free
• https://docs.google.com/document/d/1nFGazvrCvHMZJgFstlbzoHjpAVwv5DEdnaBr_5pKuHo/edit?usp=sharing

References

• Reference

Repository

• Home > Ajabbi Research > Library >
• Home > Handbook > 

Last Updated

11/05/2025

Upgrading from Java 8 to Java 12

By: Mike Peters

On a Sandy Beach: 17/04/2019

Mike is the inventor and architect of Pipi and the founder of Ajabbi.

The latest QCon weekly newsletter has a great article on the reasons to upgrade from Java 8 to 12 and the changes to Java support announced by Oracle.

Article key takeaways.

• Since Java 8 a number of useful new language features have been introduced, along with new tooling, and performance improvements particularly for garbage collection.
• When choosing to upgrade the choice you face is whether to upgrade to the latest version of Java (12) and be prepared to upgrade every six months; or upgrade to the latest LTS (11) to give yourself up to three years to think about your next upgrade.
• Don’t be tempted to ignore compiler warnings.  Deprecation is being taken much more seriously in this modern Java world, and both Java 10 and Java 11 removed APIs.  
• One of the changes from Java 9 was that internal APIs (largely those classes in packages that started with sun.misc.*) were hidden from use. APIs that are not core to the JDK have also been removed in Java 11. These changes may impact your application but there is a clear path to avoid these problems.
• Once "over the hump" of this first upgrade, it's worth at least testing the application on the latest version of Java every 6 months, for example in CI.

There is a great Google Doc here which discusses OpenJDK etc.

Is Java still Free?

A panel discussion recorded April 9 at QCon London 2019, with video, slides and transcript. The panelists talk about costs, freedom of use, who governs Java/OpenJDK and what providers are for Java infrastructure for the next 5, 10, 15 years.