[SPARK-12868][SQL] Allow adding jars from hdfs

## What changes were proposed in this pull request?
Spark 2.2 is going to be cut, it'll be great if SPARK-12868 can be resolved before that. There have been several PRs for this like [PR#16324](#16324) , but all of them are inactivity for a long time or have been closed.

This PR added a SparkUrlStreamHandlerFactory, which relies on 'protocol' to choose the appropriate
UrlStreamHandlerFactory like FsUrlStreamHandlerFactory to create URLStreamHandler.

## How was this patch tested?
1. Add a new unit test.
2. Check manually.
Before: throw an exception with " failed unknown protocol: hdfs"
<img width="914" alt="screen shot 2017-03-17 at 9 07 36 pm" src="https://cloud.githubusercontent.com/assets/8546874/24075277/5abe0a7c-0bd5-11e7-900e-ec3d3105da0b.png">

After:
<img width="1148" alt="screen shot 2017-03-18 at 11 42 18 am" src="https://cloud.githubusercontent.com/assets/8546874/24075283/69382a60-0bd5-11e7-8d30-d9405c3aaaba.png">

Author: Weiqing Yang <[email protected]>

Closes #17342 from weiqingy/SPARK-18910.

Author: weiqingy

sql/core/src/main/scala/org/apache/spark/sql/internal/SharedState.scala

@@ -17,12 +17,14 @@
 
 package org.apache.spark.sql.internal
 
+import java.net.URL
 import java.util.Locale
 
 import scala.reflect.ClassTag
 import scala.util.control.NonFatal
 
 import org.apache.hadoop.conf.Configuration
+import org.apache.hadoop.fs.FsUrlStreamHandlerFactory
 
 import org.apache.spark.{SparkConf, SparkContext, SparkException}
 import org.apache.spark.internal.Logging
@@ -154,7 +156,13 @@ private[sql] class SharedState(val sparkContext: SparkContext) extends Logging {
   }
 }
 
-object SharedState {
+object SharedState extends Logging {
+  try {
+    URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory())
+  } catch {
+    case e: Error =>
+      logWarning("URL.setURLStreamHandlerFactory failed to set FsUrlStreamHandlerFactory")
+  }
 
   private val HIVE_EXTERNAL_CATALOG_CLASS_NAME = "org.apache.spark.sql.hive.HiveExternalCatalog"
 

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -19,6 +19,7 @@ package org.apache.spark.sql
 
 import java.io.File
 import java.math.MathContext
+import java.net.{MalformedURLException, URL}
 import java.sql.Timestamp
 import java.util.concurrent.atomic.AtomicBoolean
 
@@ -2606,4 +2607,16 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
       case ae: AnalysisException => assert(ae.plan == null && ae.getMessage == ae.getSimpleMessage)
     }
   }
+
+  test("SPARK-12868: Allow adding jars from hdfs ") {
+    val jarFromHdfs = "hdfs://doesnotmatter/test.jar"
+    val jarFromInvalidFs = "fffs://doesnotmatter/test.jar"
+
+    // if 'hdfs' is not supported, MalformedURLException will be thrown
+    new URL(jarFromHdfs)
+
+    intercept[MalformedURLException] {
+      new URL(jarFromInvalidFs)
+    }
+  }
 }