[SPARK-14914][CORE] Fix Resource not closed after using, for unit tests and example

## What changes were proposed in this pull request?

This is a follow-up work of #15618.

Close file source;
For any newly created streaming context outside the withContext, explicitly close the context.

## How was this patch tested?

Existing unit tests.

Author: wm624@hotmail.com <wm624@hotmail.com>

Closes #15818 from wangmiao1981/rtest.

1 files changed, 3 insertions, 1 deletions

diff --git a/examples/src/main/scala/org/apache/spark/examples/LocalFileLR.scala b/examples/src/main/scala/org/apache/spark/examples/LocalFileLR.scala
index 3d02ce0561..a897cad02f 100644
--- a/examples/src/main/scala/org/apache/spark/examples/LocalFileLR.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/LocalFileLR.scala
@@ -51,7 +51,8 @@ object LocalFileLR {
 
     showWarning()
 
-    val lines = scala.io.Source.fromFile(args(0)).getLines().toArray
+    val fileSrc = scala.io.Source.fromFile(args(0))
+    val lines = fileSrc.getLines().toArray
     val points = lines.map(parsePoint _)
     val ITERATIONS = args(1).toInt
 
@@ -69,6 +70,7 @@ object LocalFileLR {
       w -= gradient
     }
 
+    fileSrc.close()
     println("Final w: " + w)
   }
 }