[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.

4 files changed, 6 insertions, 6 deletions

diff --git a/core/src/test/java/org/apache/spark/JavaAPISuite.java b/core/src/test/java/org/apache/spark/JavaAPISuite.java
index e6a4ab7550..a7e74c0079 100644
--- a/core/src/test/java/org/apache/spark/JavaAPISuite.java
+++ b/core/src/test/java/org/apache/spark/JavaAPISuite.java
@@ -21,6 +21,7 @@ import java.io.*;
 import java.nio.channels.FileChannel;
 import java.nio.ByteBuffer;
 import java.net.URI;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -45,7 +46,6 @@ import com.google.common.collect.Iterators;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.base.Throwables;
-import com.google.common.base.Charsets;
 import com.google.common.io.Files;
 import org.apache.hadoop.io.IntWritable;
 import org.apache.hadoop.io.Text;
@@ -1058,7 +1058,7 @@ public class JavaAPISuite implements Serializable {
     rdd.saveAsTextFile(outputDir);
     // Read the plain text file and check it's OK
     File outputFile = new File(outputDir, "part-00000");
-    String content = Files.toString(outputFile, Charsets.UTF_8);
+    String content = Files.toString(outputFile, StandardCharsets.UTF_8);
     Assert.assertEquals("1\n2\n3\n4\n", content);
     // Also try reading it in as a text file RDD
     List<String> expected = Arrays.asList("1", "2", "3", "4");
diff --git a/core/src/test/java/org/apache/spark/shuffle/sort/ShuffleInMemorySorterSuite.java b/core/src/test/java/org/apache/spark/shuffle/sort/ShuffleInMemorySorterSuite.java
index b4fa33f32a..a3502708aa 100644
--- a/core/src/test/java/org/apache/spark/shuffle/sort/ShuffleInMemorySorterSuite.java
+++ b/core/src/test/java/org/apache/spark/shuffle/sort/ShuffleInMemorySorterSuite.java
@@ -17,6 +17,7 @@
 
 package org.apache.spark.shuffle.sort;
 
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Random;
 
@@ -41,7 +42,7 @@ public class ShuffleInMemorySorterSuite {
   private static String getStringFromDataPage(Object baseObject, long baseOffset, int strLength) {
     final byte[] strBytes = new byte[strLength];
     Platform.copyMemory(baseObject, baseOffset, strBytes, Platform.BYTE_ARRAY_OFFSET, strLength);
-    return new String(strBytes);
+    return new String(strBytes, StandardCharsets.UTF_8);
   }
 
   @Test
diff --git a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
index b757ddc3b3..a79ed58133 100644
--- a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
+++ b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorterSuite.java
@@ -80,7 +80,6 @@ public class UnsafeExternalSorterSuite {
     }
   };
 
-  SparkConf sparkConf;
   File tempDir;
   @Mock(answer = RETURNS_SMART_NULLS) BlockManager blockManager;
   @Mock(answer = RETURNS_SMART_NULLS) DiskBlockManager diskBlockManager;
@@ -99,7 +98,6 @@ public class UnsafeExternalSorterSuite {
   @Before
   public void setUp() {
     MockitoAnnotations.initMocks(this);
-    sparkConf = new SparkConf();
     tempDir = Utils.createTempDir(System.getProperty("java.io.tmpdir"), "unsafe-test");
     spillFilesCreated.clear();
     taskContext = mock(TaskContext.class);
diff --git a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorterSuite.java b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorterSuite.java
index ff41768df1..90849ab0bd 100644
--- a/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorterSuite.java
+++ b/core/src/test/java/org/apache/spark/util/collection/unsafe/sort/UnsafeInMemorySorterSuite.java
@@ -17,6 +17,7 @@
 
 package org.apache.spark.util.collection.unsafe.sort;
 
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 
 import org.junit.Assert;
@@ -41,7 +42,7 @@ public class UnsafeInMemorySorterSuite {
   private static String getStringFromDataPage(Object baseObject, long baseOffset, int length) {
     final byte[] strBytes = new byte[length];
     Platform.copyMemory(baseObject, baseOffset, strBytes, Platform.BYTE_ARRAY_OFFSET, length);
-    return new String(strBytes);
+    return new String(strBytes, StandardCharsets.UTF_8);
   }
 
   @Test