[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, 10 insertions, 23 deletions

diff --git a/launcher/src/test/java/org/apache/spark/launcher/LauncherServerSuite.java b/launcher/src/test/java/org/apache/spark/launcher/LauncherServerSuite.java
index dc8fbb58d8..13f72b757f 100644
--- a/launcher/src/test/java/org/apache/spark/launcher/LauncherServerSuite.java
+++ b/launcher/src/test/java/org/apache/spark/launcher/LauncherServerSuite.java
@@ -23,11 +23,11 @@ import java.net.InetAddress;
 import java.net.Socket;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.Semaphore;
 import java.util.concurrent.TimeUnit;
 
 import org.junit.Test;
 import static org.junit.Assert.*;
-import static org.mockito.Mockito.*;
 
 import static org.apache.spark.launcher.LauncherProtocol.*;
 
@@ -69,44 +69,31 @@ public class LauncherServerSuite extends BaseSuite {
       Socket s = new Socket(InetAddress.getLoopbackAddress(),
         LauncherServer.getServerInstance().getPort());
 
-      final Object waitLock = new Object();
+      final Semaphore semaphore = new Semaphore(0);
       handle.addListener(new SparkAppHandle.Listener() {
         @Override
         public void stateChanged(SparkAppHandle handle) {
-          wakeUp();
+          semaphore.release();
         }
-
         @Override
         public void infoChanged(SparkAppHandle handle) {
-          wakeUp();
-        }
-
-        private void wakeUp() {
-          synchronized (waitLock) {
-            waitLock.notifyAll();
-          }
+          semaphore.release();
         }
       });
 
       client = new TestClient(s);
-      synchronized (waitLock) {
-        client.send(new Hello(handle.getSecret(), "1.4.0"));
-        waitLock.wait(TimeUnit.SECONDS.toMillis(10));
-      }
+      client.send(new Hello(handle.getSecret(), "1.4.0"));
+      semaphore.tryAcquire(10, TimeUnit.MILLISECONDS);
 
       // Make sure the server matched the client to the handle.
       assertNotNull(handle.getConnection());
 
-      synchronized (waitLock) {
-        client.send(new SetAppId("app-id"));
-        waitLock.wait(TimeUnit.SECONDS.toMillis(10));
-      }
+      client.send(new SetAppId("app-id"));
+      semaphore.tryAcquire(10, TimeUnit.MILLISECONDS);
       assertEquals("app-id", handle.getAppId());
 
-      synchronized (waitLock) {
-        client.send(new SetState(SparkAppHandle.State.RUNNING));
-        waitLock.wait(TimeUnit.SECONDS.toMillis(10));
-      }
+      client.send(new SetState(SparkAppHandle.State.RUNNING));
+      semaphore.tryAcquire(10, TimeUnit.MILLISECONDS);
       assertEquals(SparkAppHandle.State.RUNNING, handle.getState());
 
       handle.stop();