[TensorFlow] No Java runtime present, requesting install

[stu1130]

Environment

1. Mac 10.14.6 (Mojave)
2. GraalVM 20.1.0 Java 11

Step to reproduce:

1. install GraalVM following the [instruction](https://www.graalvm.org/docs/getting-started/macos)
2. git clone https://github.com/aws-samples/djl-demo.git
3. cd djl-demo/graalvm
4. mvn clean package -Pnative -Ptensorflow
5. target/image-classification
Loading:     100% |████████████████████████████████████████|
No Java runtime present, requesting install.

DJL uses TensorFlow JavaCpp bindings.
When building GraalVM with native mode, it shouldn't look for java during the runtime
Does JavaCpp for TensorFlow override the path of which JVM is loading?

[saudet]

Does the same thing happen with this sample project?
https://github.com/bytedeco/sample-projects/tree/master/opencv-stitching-native

[stu1130]

@saudet yes I got the same error

[saudet]

Hum, that's weird. It's not doing anything that should trigger something like that...
I wonder if that gets triggered when trying to link with JavaVM framework but not installed?
https://github.com/bytedeco/javacpp/blob/master/src/main/java/org/bytedeco/javacpp/tools/Builder.java#L187

[saudet]

Yeah, it looks like that means the JDK isn't installed on the system. I wonder how GraalVM's JDK should be installed as a framework on a Mac for this to work correctly...

[stu1130]

The weirdest part is that my colleague @frankfliu don't have such issue, but me and one of the engineer from RedHat have the same error #deepjavalibrary/djl#133
Do you have any insight on this @frankfliu ?

[saudet]

Oh, I see what's going on. Linking with the JavaVM framework actually makes it go look for libjvm.dylib, but it's not there unless the JDK is installed, which we don't need for the Java code after compiling everything AOT. Let me see how we can fix this...

[saudet]

I've fixed this in commit a59010d, but to have it applied to TensorFlow, we need to upgrade to JavaCPP 1.5.4-SNAPSHOT.
@karllessard Are you OK with adding dependencies on snapshots?

/cc @johanvos

[karllessard]

When are you planning to release it? As long as TF Java is only available as a snapshot, it's fine but a release would be certainly better (I'm a bit biased in my statement because I'm building at the moment on a platform having issues to download snapshots from OSS Sonatype, are JavaCPP snapshots deployed on this repo as well?)

[saudet]

Sonatype OSSRH as well, yes: http://bytedeco.org/builds/

What kind of issues are you having?

[karllessard]

For our readers, @saudet and I discussed in private with the problems I'm having with Sonatype but regarding this issue, I think we are good to try this JavaCPP snapshot in TensorFlow for Java.

[stu1130]

Thanks for the quick fix. @saudet
Is the patch available on 1.5.4-SNAPSHOT for macos?

[saudet]

Yes, see tensorflow/java#93

[stu1130]

Thanks! I verified the problem has been solved.

[saudet]

Fix released with JavaCPP 1.5.4. Thanks for reporting this issue!