Filter out nulls - prevent NPE

core/src/main/scala/spark/SparkContext.scala

@@ -537,6 +537,8 @@ class SparkContext(
    * filesystems), or an HTTP, HTTPS or FTP URI.
    */
   def addJar(path: String) {
+    // weird - debug why this is happening.
+    if (null == path) return
     val uri = new URI(path)
     val key = uri.getScheme match {
       case null | "file" => env.httpFileServer.addJar(new File(uri.getPath))