[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.

2 files changed, 6 insertions, 2 deletions

diff --git a/examples/src/main/java/org/apache/spark/examples/streaming/JavaCustomReceiver.java b/examples/src/main/java/org/apache/spark/examples/streaming/JavaCustomReceiver.java
index 5de56340c6..4544ad2b42 100644
--- a/examples/src/main/java/org/apache/spark/examples/streaming/JavaCustomReceiver.java
+++ b/examples/src/main/java/org/apache/spark/examples/streaming/JavaCustomReceiver.java
@@ -36,6 +36,7 @@ import java.io.BufferedReader;
 import java.io.InputStreamReader;
 import java.net.ConnectException;
 import java.net.Socket;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.regex.Pattern;
@@ -130,7 +131,8 @@ public class JavaCustomReceiver extends Receiver<String> {
       try {
         // connect to the server
         socket = new Socket(host, port);
-        reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+        reader = new BufferedReader(
+            new InputStreamReader(socket.getInputStream(), StandardCharsets.UTF_8));
         // Until stopped or connection broken continue reading
         while (!isStopped() && (userInput = reader.readLine()) != null) {
           System.out.println("Received data '" + userInput + "'");
diff --git a/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala b/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
index 5ce5778e42..d67da270a8 100644
--- a/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
@@ -20,6 +20,7 @@ package org.apache.spark.examples.streaming
 
 import java.io.{BufferedReader, InputStreamReader}
 import java.net.Socket
+import java.nio.charset.StandardCharsets
 
 import org.apache.spark.{Logging, SparkConf}
 import org.apache.spark.storage.StorageLevel
@@ -83,7 +84,8 @@ class CustomReceiver(host: String, port: Int)
      logInfo("Connecting to " + host + ":" + port)
      socket = new Socket(host, port)
      logInfo("Connected to " + host + ":" + port)
-     val reader = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"))
+     val reader = new BufferedReader(
+       new InputStreamReader(socket.getInputStream(), StandardCharsets.UTF_8))
      userInput = reader.readLine()
      while(!isStopped && userInput != null) {
        store(userInput)