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Spark leading to ClassNotFoundException for corrupt jar files instead of ZipException

 

When Jar passed via --jars that leads to following error -

  • zip END header not found

Same Jar passed as application jar file leads to following error -
  • ClassNotFoundException
These two errors are not contradictory. They mean Spark is touching the Jar in 2 completely different code paths.


--jars Jars are:
  • Downloaded
  • Immediately unpacked/ inspected
  • Added to executor classpath eagerly.
Thus if Jar is bad. Spark tries to open it as ZIP, which leads to ZipException.


When used as application Jar:
  • Spark does minimal Zip validation.
  • Only checks enough to start
  • Loads manifest + class index
  • Attempts to resolve --class
if:
  • The Jar opens.
  • But the expected class isn't there, which leads to ClassNotFoundException
So:
  • Spark never deeply unzips it
  • Corruption in unused entries may go unnoticed

Outcomes:
  • As app JAR -> Spark reads just enough -> ClassNotFoundException
  • As --jars -> Spark fully opens ZIP -> zip END header not found

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