java: ITClient: name background threads

The ITClient test has several background threads that perform tasks
while the test is running. Naming these threads makes it easier to
understand what happened when wading through the test log.

This patch also squelches an unrelated warning from TempDirUtils due to
not specifying @OverRide on a Thread's run() method.

Change-Id: I9874b088cc8e77707fc913df3de1d1592c1de6c3
Reviewed-on: http://gerrit.cloudera.org:8080/12677
Tested-by: Kudu Jenkins
Reviewed-by: Adar Dembo <[email protected]>

java/kudu-client/src/test/java/org/apache/kudu/client/ITClient.java

@@ -92,20 +92,13 @@ public void setUp() throws Exception {
 
   @Test(timeout = TEST_TIMEOUT_SECONDS)
   public void test() throws Exception {
-
-    UncaughtExceptionHandler uncaughtExceptionHandler = new UncaughtExceptionHandler();
-
-    ArrayList<Thread> threads = new ArrayList<>();
-    Thread chaosThread = new Thread(new ChaosThread());
-    Thread writerThread = new Thread(new WriterThread());
-    Thread scannerThread = new Thread(new ScannerThread());
-
-    threads.add(chaosThread);
-    threads.add(writerThread);
-    threads.add(scannerThread);
+    List<Thread> threads = new ArrayList<>();
+    threads.add(new Thread(new ChaosThread(), "chaos-test-thread"));
+    threads.add(new Thread(new WriterThread(), "writer-test-thread"));
+    threads.add(new Thread(new ScannerThread(), "scanner-test-thread"));
 
     for (Thread thread : threads) {
-      thread.setUncaughtExceptionHandler(uncaughtExceptionHandler);
+      thread.setUncaughtExceptionHandler(new UncaughtExceptionHandler());
       thread.start();
     }
 

java/kudu-test-utils/src/main/java/org/apache/kudu/test/TempDirUtils.java

@@ -86,6 +86,7 @@ public static File makeTempDirectory(String prefix, DeleteOnExit deleteRecursive
   private static void registerToRecursivelyDeleteOnShutdown(Path path) {
     final Path absPath = path.toAbsolutePath();
     Runtime.getRuntime().addShutdownHook(new Thread() {
+      @Override
       public void run() {
         File dir = absPath.toFile();
         if (!dir.exists()) return;