Troubleshooting¶

Apache Arrow: InaccessibleObjectException on the first action¶

Results are decoded with Apache Arrow, which reaches into internal java.nio buffers. On JDK 17 and newer an unconfigured JVM throws on the first collect(), show(), or count(), for example:

java.lang.RuntimeException: Failed to initialize MemoryUtil
Caused by: java.lang.InaccessibleObjectException: Unable to make ... accessible:
module java.base does not "opens java.nio" to unnamed module

Open the two modules on the application JVM:

--add-opens=java.base/java.nio=ALL-UNNAMED
--add-opens=java.base/sun.nio.ch=ALL-UNNAMED

In sbt set them on the forked JVM (javaOptions ++= ... with run / fork := true); for a packaged app pass them to java directly. See Installation.

gRPC connection problems¶

Connection refused / UNAVAILABLE: confirm the server is running and reachable at the host and port in your sc:// URL (default port 15002). Test with `bash -c "