[SPARK-13823][SPARK-13397][SPARK-13395][CORE] More warnings, StandardCharset follow up

## What changes were proposed in this pull request?

Follow up to https://github.com/apache/spark/pull/11657

- Also update `String.getBytes("UTF-8")` to use `StandardCharsets.UTF_8`
- And fix one last new Coverity warning that turned up (use of unguarded `wait()` replaced by simpler/more robust `java.util.concurrent` classes in tests)
- And while we're here cleaning up Coverity warnings, just fix about 15 more build warnings

## How was this patch tested?

Jenkins tests

Author: Sean Owen <sowen@cloudera.com>

Closes #11725 from srowen/SPARK-13823.2.

1 files changed, 17 insertions, 21 deletions

diff --git a/common/network-shuffle/src/test/java/org/apache/spark/network/sasl/SaslIntegrationSuite.java b/common/network-shuffle/src/test/java/org/apache/spark/network/sasl/SaslIntegrationSuite.java
index 0ea631ea14..5322fcd781 100644
--- a/common/network-shuffle/src/test/java/org/apache/spark/network/sasl/SaslIntegrationSuite.java
+++ b/common/network-shuffle/src/test/java/org/apache/spark/network/sasl/SaslIntegrationSuite.java
@@ -20,6 +20,7 @@ package org.apache.spark.network.sasl;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicReference;
 
 import com.google.common.collect.Lists;
@@ -197,26 +198,23 @@ public class SaslIntegrationSuite {
 
       final AtomicReference<Throwable> exception = new AtomicReference<>();
 
+      final CountDownLatch blockFetchLatch = new CountDownLatch(1);
       BlockFetchingListener listener = new BlockFetchingListener() {
         @Override
-        public synchronized void onBlockFetchSuccess(String blockId, ManagedBuffer data) {
-          notifyAll();
+        public void onBlockFetchSuccess(String blockId, ManagedBuffer data) {
+          blockFetchLatch.countDown();
         }
-
         @Override
-        public synchronized void onBlockFetchFailure(String blockId, Throwable t) {
+        public void onBlockFetchFailure(String blockId, Throwable t) {
           exception.set(t);
-          notifyAll();
+          blockFetchLatch.countDown();
         }
       };
 
-      String[] blockIds = new String[] { "shuffle_2_3_4", "shuffle_6_7_8" };
-      OneForOneBlockFetcher fetcher = new OneForOneBlockFetcher(client1, "app-2", "0",
-        blockIds, listener);
-      synchronized (listener) {
-        fetcher.start();
-        listener.wait();
-      }
+      String[] blockIds = { "shuffle_2_3_4", "shuffle_6_7_8" };
+      OneForOneBlockFetcher fetcher = new OneForOneBlockFetcher(client1, "app-2", "0", blockIds, listener);
+      fetcher.start();
+      blockFetchLatch.await();
       checkSecurityException(exception.get());
 
       // Register an executor so that the next steps work.
@@ -240,24 +238,22 @@ public class SaslIntegrationSuite {
       client2 = clientFactory2.createClient(TestUtils.getLocalHost(),
         blockServer.getPort());
 
+      final CountDownLatch chunkReceivedLatch = new CountDownLatch(1);
       ChunkReceivedCallback callback = new ChunkReceivedCallback() {
         @Override
-        public synchronized void onSuccess(int chunkIndex, ManagedBuffer buffer) {
-          notifyAll();
+        public void onSuccess(int chunkIndex, ManagedBuffer buffer) {
+          chunkReceivedLatch.countDown();
         }
-
         @Override
-        public synchronized void onFailure(int chunkIndex, Throwable t) {
+        public void onFailure(int chunkIndex, Throwable t) {
           exception.set(t);
-          notifyAll();
+          chunkReceivedLatch.countDown();
         }
       };
 
       exception.set(null);
-      synchronized (callback) {
-        client2.fetchChunk(streamId, 0, callback);
-        callback.wait();
-      }
+      client2.fetchChunk(streamId, 0, callback);
+      chunkReceivedLatch.await();
       checkSecurityException(exception.get());
     } finally {
       if (client1 != null) {