[SPARK-15622][SQL] Wrap the parent classloader of Janino's classloader in the ParentClassLoader.

## What changes were proposed in this pull request?
At https://github.com/aunkrig/janino/blob/janino_2.7.8/janino/src/org/codehaus/janino/ClassLoaderIClassLoader.java#L80-L85, Janino's classloader throws the exception when its parent throws a ClassNotFoundException with a cause set. However, it does not throw the exception when there is no cause set. Seems we need to use a special ClassLoader to wrap the actual parent classloader set to Janino handle this behavior.

## How was this patch tested?
I have reverted the workaround made by https://issues.apache.org/jira/browse/SPARK-11636 ( https://github.com/apache/spark/compare/master...yhuai:SPARK-15622?expand=1#diff-bb538fda94224dd0af01d0fd7e1b4ea0R81) and `test-only *ReplSuite -- -z "SPARK-2576 importing implicits"` still passes the test (without the change in `CodeGenerator`, this test does not pass with the change in `ExecutorClassLoader `).

Author: Yin Huai <yhuai@databricks.com>

Closes #13366 from yhuai/SPARK-15622.

1 files changed, 1 insertions, 7 deletions

diff --git a/repl/src/main/scala/org/apache/spark/repl/ExecutorClassLoader.scala b/repl/src/main/scala/org/apache/spark/repl/ExecutorClassLoader.scala
index 4a15d52b57..2f07395edf 100644
--- a/repl/src/main/scala/org/apache/spark/repl/ExecutorClassLoader.scala
+++ b/repl/src/main/scala/org/apache/spark/repl/ExecutorClassLoader.scala
@@ -79,13 +79,7 @@ class ExecutorClassLoader(
         case e: ClassNotFoundException =>
           val classOption = findClassLocally(name)
           classOption match {
-            case None =>
-              // If this class has a cause, it will break the internal assumption of Janino
-              // (the compiler used for Spark SQL code-gen).
-              // See org.codehaus.janino.ClassLoaderIClassLoader's findIClass, you will see
-              // its behavior will be changed if there is a cause and the compilation
-              // of generated class will fail.
-              throw new ClassNotFoundException(name)
+            case None => throw new ClassNotFoundException(name, e)
             case Some(a) => a
           }
       }