Mike's Notes
Notes on Java remaining open.
- The most precise explanations I've heard.
- Develop on Java 12 OpenJDK.
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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.
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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.
