Fixed URI validation for jar file

Author: sarutak

core/src/main/scala/org/apache/spark/deploy/ClientArguments.scala

@@ -75,7 +75,7 @@ private[spark] class ClientArguments(args: Array[String]) {
 
       if (!ClientArguments.isValidJarUrl(_jarUrl)) {
         println(s"Jar url '${_jarUrl}' is not in valid format.")
-        println(s"Must be a jar file path in URL format (e.g. hdfs://XX.jar, file://XX.jar)")
+        println(s"Must be a jar file path in URL format (e.g. hdfs://XX.jar, file:///XX.jar)")
         printUsageAndExit(-1)
       }
 
@@ -119,7 +119,7 @@ object ClientArguments {
   def isValidJarUrl(s: String): Boolean = {
     try {
       val uri = new URI(s)
-      uri.getScheme != null && uri.getAuthority != null && s.endsWith("jar")
+      uri.getScheme != null && uri.getPath != null && uri.getPath.endsWith(".jar")
     } catch {
       case _: URISyntaxException => false
     }

core/src/test/scala/org/apache/spark/deploy/ClientSuite.scala

@@ -23,7 +23,14 @@ import org.scalatest.Matchers
 class ClientSuite extends FunSuite with Matchers {
   test("correctly validates driver jar URL's") {
     ClientArguments.isValidJarUrl("http://someHost:8080/foo.jar") should be (true)
-    ClientArguments.isValidJarUrl("file://some/path/to/a/jarFile.jar") should be (true)
+
+    // file scheme with authority is valid.
+    ClientArguments.isValidJarUrl("file://somehost/path/to/a/jarFile.jar") should be (true)
+
+    // file scheme without authority is not valid.
+    ClientArguments.isValidJarUrl("file://jarFile.jar") should be (false)
+
+    // file scheme without authority but with triple slash is valid.
     ClientArguments.isValidJarUrl("file:///some/path/to/a/jarFile.jar") should be (true)
     ClientArguments.isValidJarUrl("hdfs://someHost:1234/foo.jar") should be (true)