Forum Discussion
Microsoft EmployeeCustom Libraries in Fabric Notebook Environment
Hi cahenning,
The import fails due to a known limitation in Fabric Notebooks — the Scala REPL doesn't recognize classes from dynamically added JARs at compile time.
As a workaround, you can use reflection to interact with the class or repackage your code as a fat JAR (including all dependencies) and try again. Direct import may not work unless Microsoft updates the REPL classloading behavior.
Regards,
Vinay Pabbu
Super UserHi cahenning ,
I get where you’re coming from, this can be confusing. Even if you see the JAR files listed with sparkContext.listJars, sometimes Fabric Notebooks have a few quirks with actually making those classes available for import in the notebook session.
A couple things I’d check:
- Make sure the JARs are uploaded to the right scope (some environments want them at workspace level, some at notebook level, and sometimes per-session).
- Try restarting the notebook kernel after uploading the JARs, just to be sure the new libraries are loaded fresh.
- Double check the JAR isn’t missing dependencies – sometimes a JAR works in Synapse because of environment differences, but Fabric might not have those extra libraries by default.
- Also, confirm the class path in your import matches exactly what’s inside the JAR (it’s easy to miss a package path or typo).
If you’ve tried all that, sometimes it’s just a limitation in how Fabric handles class loading for custom libraries. You could try submitting the JAR via a %run or %dep magic command, if Fabric supports those (I’ve seen this help in some Spark setups).
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