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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Issue with arrow-c JNI and GraalVM 25","articleBody":"### Describe the enhancement requested\n\nI'm aware that graalvm is probably not supported, but I'm raising this as it might be simple fix.\n\nThere is a issue with `env-\u003eFindClass` 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-\u003eFindClass` wont be able to  find a classes at\n\nhttps://github.com/apache/arrow-java/blob/34060eb491a870f5ede5d30e007060b8310dc64f/c/src/main/cpp/jni_wrapper.cc#L60\n\nThe issues are at:\n\nhttps://github.com/apache/arrow-java/blob/34060eb491a870f5ede5d30e007060b8310dc64f/c/src/main/cpp/jni_wrapper.cc#L334-L342\n\nwhere 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.\n\n```java\nkObjectClass = CreateGlobalClassReference(env, \"java/lang/Object\");\nkRuntimeExceptionClass =\n    CreateGlobalClassReference(env, \"java/lang/RuntimeException\");\nkPrivateDataClass =\n    CreateGlobalClassReference(env, \"org/apache/arrow/c/jni/PrivateData\");\nkCDataExceptionClass =\n    CreateGlobalClassReference(env, \"org/apache/arrow/c/jni/CDataJniException\");\nkStreamPrivateDataClass = CreateGlobalClassReference(\n    env, \"org/apache/arrow/c/ArrayStreamExporter$ExportedArrayStreamPrivateData\");\n```\n\nlooking at the spec, \n\n- https://docs.oracle.com/en/java/javase/11/docs/specs/jni/functions.html#findclass\n- https://docs.oracle.com/en/java/javase/21/docs/specs/jni/functions.html#findclass\n\nit says correct format is without `L` and ';' for non array classes.\n\nI 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I can't make `18.3` run locally as instructions at https://arrow.apache.org/docs/developers/java/building.html are outdated with change to new repo \n\nalso, one small request, can \n\nhttps://github.com/apache/arrow-java/blob/34060eb491a870f5ede5d30e007060b8310dc64f/c/src/main/cpp/jni_wrapper.cc#L330-L331\n\nreturn error returned by `vm-\u003eGetEnv` rather than `JNI_ERR`","author":{"url":"https://github.com/milenkovicm","@type":"Person","name":"milenkovicm"},"datePublished":"2025-10-02T09:04:19.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/866/arrow-java/issues/866"}