Random NoClassDefFound Error when running job

[abaet]

We are running a job on a cluster with DBR 10.4 LTS Spark 3.2.1 and scala 2.12. Cluster is using 4 workers (spot instances) .The driver is not a spot instance

Randomly ( only on one environment and not all executions), we are getting the following error : java.lang.NoClassDefFoundError: Could not initialize class path.to.one.of.our.Class$

The class does exists and is present in the jar we are loading as a dependant library in the job task definition. The jar was compiled with the same versions (3.2.1/2.12)

The environment is identical to other working ones and as I 've mentionned, just relaunching the same failing job  once makes it succeed, without changing anything.

Any ideas regarding what could the problem possibly be ?

[Kaniz_Fatma]

Hi @abaet, 

• The error message suggests that the class failed to initialize. Check if there’s any uncaught exception during static initialization (e.g., in a static block or when creating static variables). If an exception occurs during class loading, it can lead to this error¹.
• Verify that the static block in your PropHolder class (or any other class involved) doesn’t throw an exception. You might need to add proper exception handling to identify the issue.