[SPARK-13823][CORE][STREAMING][SQL] Always specify Charset in String <-> byte[] conversions (and remaining Coverity items)

## What changes were proposed in this pull request?

- Fixes calls to `new String(byte[])` or `String.getBytes()` that rely on platform default encoding, to use UTF-8
- Same for `InputStreamReader` and `OutputStreamWriter` constructors
- Standardizes on UTF-8 everywhere
- Standardizes specifying the encoding with `StandardCharsets.UTF-8`, not the Guava constant or "UTF-8" (which means handling `UnuspportedEncodingException`)
- (also addresses the other remaining Coverity scan issues, which are pretty trivial; these are separated into commit https://github.com/srowen/spark/commit/1deecd8d9ca986d8adb1a42d315890ce5349d29c )

## How was this patch tested?

Jenkins tests

Author: Sean Owen <sowen@cloudera.com>

Closes #11657 from srowen/SPARK-13823.

1 files changed, 2 insertions, 1 deletions

diff --git a/graphx/src/test/scala/org/apache/spark/graphx/GraphLoaderSuite.scala b/graphx/src/test/scala/org/apache/spark/graphx/GraphLoaderSuite.scala
index bff9f328d4..e55b05fa99 100644
--- a/graphx/src/test/scala/org/apache/spark/graphx/GraphLoaderSuite.scala
+++ b/graphx/src/test/scala/org/apache/spark/graphx/GraphLoaderSuite.scala
@@ -20,6 +20,7 @@ package org.apache.spark.graphx
 import java.io.File
 import java.io.FileOutputStream
 import java.io.OutputStreamWriter
+import java.nio.charset.StandardCharsets
 
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.util.Utils
@@ -30,7 +31,7 @@ class GraphLoaderSuite extends SparkFunSuite with LocalSparkContext {
     withSpark { sc =>
       val tmpDir = Utils.createTempDir()
       val graphFile = new File(tmpDir.getAbsolutePath, "graph.txt")
-      val writer = new OutputStreamWriter(new FileOutputStream(graphFile))
+      val writer = new OutputStreamWriter(new FileOutputStream(graphFile), StandardCharsets.UTF_8)
       for (i <- (1 until 101)) writer.write(s"$i 0\n")
       writer.close()
       try {