bundling native libs in jars or modules

Tom Schindl tom.schindl at bestsolution.at
Thu May 17 19:59:06 UTC 2018

To answer my own question the trick swt uses is to encode the build-id into the dll/so so it never needs to delete a file

See http://git.eclipse.org/c/platform/eclipse.platform.swt.git/tree/bundles/org.eclipse.swt/Eclipse%20SWT%20PI/common/org/eclipse/swt/internal/Library.java#n144


Von meinem iPhone gesendet

> Am 17.05.2018 um 21:50 schrieb Tom Schindl <tom.schindl at bestsolution.at>:
> Did you check how SWT does addresses the problem? If you run it outside of OSGi it needs to deal with this problem as well.
> Tom
> Von meinem iPhone gesendet
>> Am 17.05.2018 um 21:25 schrieb Johan Vos <johan.vos at gluonhq.com>:
>> Note: This is different from what is discussed in
>> http://mail.openjdk.java.net/pipermail/openjfx-dev/2018-April/021762.html
>> The following text is about bundling native code within a jar, and doesn't
>> talk about how to deal with platform-specific libraries in generic jar
>> files.
>> At this moment, the standalone SDK for JavaFX 11-ea works fine, and javafx
>> apps can be executed since the javafx jars will load the required native
>> code from the libs that are part of the SDK.
>> When we want to download the javafx modules as modules (or jars with
>> module-info), we don't have a local SDK with native libraries. The native
>> libraries need to come with the downloaded jar. There are a number of
>> options to do this, and a number of ongoing discussions (e.g. see
>> http://mail.openjdk.java.net/pipermail/panama-dev/2018-April/001541.html).
>> In summary, jmods already have support for native code but they are not
>> scoped at runtime, and jars don't have a standard way for supporting native
>> code.
>> I hope there will be a long-term solution for this in the VM in the future,
>> but clearly we can't rely on this for the 11 release.
>> Hence, we need to provide some JavaFX-specific fixes.
>> Just to try the mechanism, I created a quick (and dirty) workaround in the
>> NativeLibLoader. I committed it to a nativelibs branch of my openjfx fork:
>> https://github.com/johanvos/openjdk-jfx/commit/f2c4c57a6197634e9c3bc1298ea14700057155a3
>> The good thing is that all JavaFX native lib loading is already delegated
>> to the NativeLibLoader, so I only had to patch one file.
>> I modified the generated javafx.graphics.jar to include all libs that are
>> generated (something that can be automated in a gradle task), and could
>> successfully run javafx apps using
>> java -p /path/to/my/jars --add-modules javafx.controls
>> without specifying java.library.path or native libs or so.
>> This works for jars that I put myself on the classpath, hence it should
>> also work for jars downloaded from maven central etc.
>> In case there will be a standard for bundling native libs with jar files in
>> a future JVM, we can remove this hack. But even in the meantime, there are
>> better solutions.
>> One of the best options I think we should consider is using JavaCPP (
>> https://github.com/bytedeco/javacpp)  . The main author of JavaCPP, Samuel
>> Audet (in cc) describes here (
>> https://github.com/tensorflow/tensorflow/issues/18397#issuecomment-381371636)
>> why my hack will fail on Windows.
>> Another advantage of JavaCPP is that it is proven to work on ios and
>> Android as well. Actually, that would allow us to get rid of the
>> ios-specific code that is currently in NativeLibLoader.java.
>> Again, this is only tackling the issue of bunding native code with jars and
>> not dealing with platform-specific resolution (although JavaCPP can help
>> there as well).
>> - Johan

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