Github user sryza commented on a diff in the pull request:
https://github.com/apache/spark/pull/119#discussion_r10507644
--- Diff: core/src/main/scala/org/apache/spark/SparkContext.scala ---
@@ -130,6 +130,16 @@ class SparkContext(
val isLocal = (master == "local" || master.startsWith("local["))
+ // Create a classLoader for use by the driver so that jars added via
addJar are available to the
+ // driver. Do this before all other initialization so that any thread
pools created for this
+ // SparkContext uses the class loader.
+ // Note that this is config-enabled as classloaders can introduce subtle
side effects
+ private[spark] val classLoader = if
(conf.getBoolean("spark.driver.loadAddedJars", false)) {
+ val loader = new SparkURLClassLoader(Array.empty[URL],
this.getClass.getClassLoader)
+ Thread.currentThread.setContextClassLoader(loader)
--- End diff --
Ah, ok, I understand now. In that case, to make things simpler, would it
possibly make sense to not load the jars to the current thread and only load
them for the SparkContext/executors? Classloader stuff can be confusing to
deal with and keeping it as isolated as possible could make things easier for
users. This would also line up a little more with how the MR distributed cache
works - jars that get added to it don't become accessible for to driver code.
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