[Native Image] Missing support for `ServiceLoader` services registered via `module-info`

[JaroslavTulach]

Describe the Issue

Java Platform Module System defines a way to register services to be located by ServiceLoader. However there seems to be no support for such registrations in native image.

Using the latest version of GraalVM can resolve many issues.

• I tried with the latest version of GraalVM.

GraalVM Version

I tried two versions:

• GraalVM CE 21.0.2+13.1 (build 21.0.2+13-jvmci-23.1-b30)
• Oracle GraalVM 23.0.1+11.1 (build 23.0.1+11-jvmci-b01)

None of them works the way it "should". Looking at the code of ServiceLoaderFeature explains why it is not working - there is no ModuleLayer related code at all - which is probably necessary to extract information from the module-info.class of the modules on module path.

Operating System and Version

Tested on Ubuntu, but this is cross OS problem

Diagnostic Flag Confirmation

• I tried the -H:ThrowMissingRegistrationErrors= flag.

Run Command

I have prepared a special repository with NativeImageModuleDemo with a demo Maven project, follow the read me that suggests to:

NativeImageModularDemo$ mvn clean install
NativeImageModularDemo$ mvn -q -Pjvm -f api exec:exec
NativeImageModularDemo with following modules:
  Api
Found no API provider. Include Impl JPMS module!
NativeImageModularDemo$ mvn -q -Pjvm -f impl exec:exec
NativeImageModularDemo with following modules:
  Api
  Impl
Hi from Impl!

e.g. two modules Api and Impl are enabled and Hi from Impl! gets printed. While with native-image:

NativeImageModularDemo$ mvn clean install -Pnative
NativeImageModularDemo$ ./impl/target/NativeImageModularDemo
NativeImageModularDemo with following modules:
  Impl
  Api
Found no API provider. Fix native-image support for modular ServiceLoader!

e.g. two modules are enabled, but the ServiceLoader.load finds no implementation of the interface it is looking for.

Expected Behavior

Native image version should work just like the JVM one:

NativeImageModularDemo$ mvn clean install -Pnative
NativeImageModularDemo$ ./impl/target/NativeImageModularDemo
NativeImageModularDemo with following modules:
  Impl
  Api
Hi from Impl!

Actual Behavior

NativeImageModularDemo$ mvn clean install -Pnative
NativeImageModularDemo$ ./impl/target/NativeImageModularDemo
NativeImageModularDemo with following modules:
  Impl
  Api
Found no API provider. Fix native-image support for modular ServiceLoader!

Steps to Reproduce

I have prepared a special repository with NativeImageModuleDemo with a demo Maven project, follow the read me that suggests to:

NativeImageModularDemo$ mvn clean install
NativeImageModularDemo$ mvn -q -Pjvm -f api exec:exec
NativeImageModularDemo with following modules:
  Api
Found no API provider. Include Impl JPMS module!
NativeImageModularDemo$ mvn -q -Pjvm -f impl exec:exec
NativeImageModularDemo with following modules:
  Api
  Impl
Hi from Impl!

e.g. two modules Api and Impl are enabled and Hi from Impl! gets printed. While with native-image:

NativeImageModularDemo$ mvn clean install -Pnative
NativeImageModularDemo$ ./impl/target/NativeImageModularDemo
NativeImageModularDemo with following modules:
  Impl
  Api
Found no API provider. Fix native-image support for modular ServiceLoader!

e.g. two modules are enabled, but the ServiceLoader.load finds no implementation of the interface it is looking for.

Additional Context

No response

Run-Time Log Output and Error Messages

No response

[wirthi]

Thanks Jaroslav for reporting this. I suspect this is a duplicate of #7634 / GR-49635. @olpaw can you confirm?

[olpaw]

I suspect this is a duplicate of #7634 / GR-49635. @olpaw can you confirm?

Correct. But I prefer @JaroslavTulach s issue as it is more recent.

[olpaw]

I will look into that soon 🤞

[olpaw]

@JaroslavTulach I debugged this. The parameterless constructor for a service impl. class gets correctly registered for reflective access and the ServiceLoader at runtime is almost able to do the right thing. But it relies on using LazyClassPathLookupIterator which then refuses to use the parameterless constructor because the implementation class is in a named module. See https://github.com/openjdk/jdk/blob/52382e285fdf853c01605f8e0d7f3f5d34965802/src/java.base/share/classes/java/util/ServiceLoader.java#L1228

Turns out we do not correctly implement ServicesCatalog retrieval at image image runtime. If we fix that then java.util.ServiceLoader.ModuleServicesLookupIterator will be responsible to instantiating the ServiceLoader impl. (as it should be anyways in this case).

I will find someone to fix this hopefully next week.

[JaroslavTulach]

Thank you @olpaw for investigating the issue. I tried to workaround the problem by loading the services in build time, but no luck so far. Was there any progress on your side?

[olpaw]

Yes, this is right now in the process of getting fixed by @ivan-ristovic

[ivan-ristovic]

Hi @JaroslavTulach , the PR that adresses this issue is up: #10202