Critical Description
With `spark-submit`, jars specified via `--jars` are added to distributed cache in `yarn-cluster` mode. The executor should add cached jars to classpath. However,
sc.parallelize(0 to 10, 10).map { i =>
System.getProperty("java.class.path")
}.collect().foreach(println)
shows only system jars, `app.jar`, and `spark.jar` but not other jars in the distributed cache.
The workaround is using assembly jar.