rebooting OpenJDK mobile

Rony rony.flatscher at
Sun Jun 30 11:45:37 UTC 2019

Hi Johan,

would it still be possible to compile Java classes and load them at runtime?


Rony G. Flatscher (mobil/e)

> Am 28.06.2019 um 16:09 schrieb Johan Vos <johan.vos at>:
> Hi,
> After a long time, it is a good moment now to restart the public work in
> the OpenJDK Mobile project.
> In the past, we had a repository with code based on OpenJDK 9 that allows
> to build the class libraries (including native code) and one or more VM's,
> for Android and iOS.
> While this works, we still have the limitation on iOS where dynamic code is
> not allowed, hence a JIT is not an option. The Zero VM works there
> (interpreter mode) but is slow.
> Today, we can use the GraalVM AOT compiler to compile the code at build
> time. We can link the compiled Java code with native libraries compiled for
> the target OS, and create executables. Most of the VM functionality is
> provided by a very small set of files in SubstrateVM (linked to by GraalVM
> native image)
> We already did this for iOS, based on Java 11 (see
> and JavaFX 13.
> (see our announcement at  The
> diff to the upstream code is remarkably small.
> It is my goal now to use project Skara to create a synchronized fork of the
> OpenJDK master, and to push the changes required to build the native libs
> for the core libraries in there.
> Ultimately, it would be ideal if all required changes can go upstream.
> At this moment, this is iOS only, but there are no showstoppers to do this
> for Android as well. The architectures are pretty similar.
> - Johan

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