Issue with arrow-c JNI and GraalVM 25

[milenkovicm]

Describe the enhancement requested

I'm aware that graalvm is probably not supported, but I'm raising this as it might be simple fix.

There is a issue with env->FindClass in arrow-c when used with graalvm 25 (native image creates a shared library) Even all required classes are exposed for JNI in graalvm configuration env->FindClass wont be able to find a classes at

arrow-java/c/src/main/cpp/jni_wrapper.cc

Line 60 in 34060eb

jclass local_class = env->FindClass(class_name);

The issues are at:

arrow-java/c/src/main/cpp/jni_wrapper.cc

Lines 334 to 342 in 34060eb

	kObjectClass = CreateGlobalClassReference(env, "Ljava/lang/Object;");
	kRuntimeExceptionClass =
	CreateGlobalClassReference(env, "Ljava/lang/RuntimeException;");
	kPrivateDataClass =
	CreateGlobalClassReference(env, "Lorg/apache/arrow/c/jni/PrivateData;");
	kCDataExceptionClass =
	CreateGlobalClassReference(env, "Lorg/apache/arrow/c/jni/CDataJniException;");
	kStreamPrivateDataClass = CreateGlobalClassReference(
	env, "Lorg/apache/arrow/c/ArrayStreamExporter$ExportedArrayStreamPrivateData;");

where class names have L and ; at the start and end of the class name, so changing class names from Ljava/lang/Object; to java/lang/Object (and all other classes) will make problem go away.

kObjectClass = CreateGlobalClassReference(env, "java/lang/Object");
kRuntimeExceptionClass =
    CreateGlobalClassReference(env, "java/lang/RuntimeException");
kPrivateDataClass =
    CreateGlobalClassReference(env, "org/apache/arrow/c/jni/PrivateData");
kCDataExceptionClass =
    CreateGlobalClassReference(env, "org/apache/arrow/c/jni/CDataJniException");
kStreamPrivateDataClass = CreateGlobalClassReference(
    env, "org/apache/arrow/c/ArrayStreamExporter$ExportedArrayStreamPrivateData");

looking at the spec,

• https://docs.oracle.com/en/java/javase/11/docs/specs/jni/functions.html#findclass
• https://docs.oracle.com/en/java/javase/21/docs/specs/jni/functions.html#findclass

it says correct format is without L and ';' for non array classes.

I did manage to fix this in 18.1 which could be built locally, unfortunately I can't make 18.3 run locally as instructions at https://arrow.apache.org/docs/developers/java/building.html are outdated with change to new repo

also, one small request, can

arrow-java/c/src/main/cpp/jni_wrapper.cc

Lines 330 to 331 in 34060eb

	if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION) != JNI_OK) {
	return JNI_ERR;

return error returned by vm->GetEnv rather than JNI_ERR

[lidavidm]

Would you be willing to file a PR? Note that GraalVM is not a currently supported configuration (though we would appreciate contributions for that too)

[milenkovicm]

I have no problem contributing; the issue is I could not set up the development environment to work with this version (I've used the version before you split to a new repo), so if there is up-to-date development setup, please let me know.

[milenkovicm]

@lidavidm I have opened #867 that should fix error.