Getting ready for OpenJDK 11 and OpenJFX

[Graham Norris]

As discussed in some other topics, things are changing in Java, and these changes will in many cases cause problems for existing applications.

There are two potentially show-stopping changes for Polarbar users. First is that there's no pre-built Java 11 binaries for 32-bit Linux, Mac or Windows systems. Second is that there's no pre-built Java 11 binaries for OS/2 at all that I'm aware of. Note that class files built with version "n" of the JDK won't run using earlier versions of Java unless cross-compiled, and that is rare (and a pain to make work!) which means new builds of Polarbar won't work on old Javas.

In order to get ready for OpenJDK 11 and OpenJFX, you need to be able to install OpenJDK 11 from https://jdk.java.net/11/ or build it yourself and install it. Then you need to be able to install OpenJFX SDK (not jmods) from https://openjfx.io/openjfx-docs/ or build it yourself and install it. In either case, do *not* try to put OpenJFX files in directories of the same name in OpenJDK. Once you've done this, you need to be able to run the OpenJFX "Hello World" program also found on openjfx.io.

Once you've done this, you'll be ready to test a Polarbar build built on OpenJDK 11 and OpenJFX.

It should also be possible to run an existing Polarbar build on this combination of OpenJDK and OpenJFX, however, I have only tried this using my own Polarbar build, built using Oracle JDK 8, and which is packaged as a jar. (Running Polarbar from a jar changes the way Java behaves compared to running if from a zip files or from bare class files, so YMMV.)

Hint for those trying this: --add-modules=ALL-MODULE-PATH is a useful shortcut to specifying all the JavaFX jars you will need from OpenJFX's lib directory which you will specify with --module-path.

Graham.