Java 11 migrate remaining q-r (#1121)

* Moves queue-load-leveling to Java 11

* Moves reactor to Java 11

* Moves reader-writer-lock to Java 11

* Moves repository to Java 11

* Moves resource-acquisition-is-initialization to Java 11

* Moves retry to Java 11

* Moves role-object to Java 11

queue-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/App.java

@@ -78,17 +78,17 @@ public class App {
 
     try {
       // Create a MessageQueue object.
-      MessageQueue msgQueue = new MessageQueue();
+      var msgQueue = new MessageQueue();
 
       LOGGER.info("Submitting TaskGenerators and ServiceExecutor threads.");
 
       // Create three TaskGenerator threads. Each of them will submit different number of jobs.
-      final Runnable taskRunnable1 = new TaskGenerator(msgQueue, 5);
-      final Runnable taskRunnable2 = new TaskGenerator(msgQueue, 1);
-      final Runnable taskRunnable3 = new TaskGenerator(msgQueue, 2);
+      final var taskRunnable1 = new TaskGenerator(msgQueue, 5);
+      final var taskRunnable2 = new TaskGenerator(msgQueue, 1);
+      final var taskRunnable3 = new TaskGenerator(msgQueue, 2);
 
       // Create e service which should process the submitted jobs.
-      final Runnable srvRunnable = new ServiceExecutor(msgQueue);
+      final var srvRunnable = new ServiceExecutor(msgQueue);
 
       // Create a ThreadPool of 2 threads and
       // submit all Runnable task for execution to executor..

queue-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/MessageQueue.java

@@ -40,7 +40,7 @@ public class MessageQueue {
 
   // Default constructor when called creates Blocking Queue object. 
   public MessageQueue() {
-    this.blkQueue = new ArrayBlockingQueue<Message>(1024);
+    this.blkQueue = new ArrayBlockingQueue<>(1024);
   }
 
   /**
@@ -62,13 +62,11 @@ public class MessageQueue {
    * them. Retrieves and removes the head of this queue, or returns null if this queue is empty.
    */
   public Message retrieveMsg() {
-    Message retrievedMsg = null;
     try {
-      retrievedMsg = blkQueue.poll();
+      return blkQueue.poll();
     } catch (Exception e) {
       LOGGER.error(e.getMessage());
     }
-
-    return retrievedMsg;
+    return null;
   }
-}
+}

queue-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/ServiceExecutor.java

@@ -46,7 +46,7 @@ public class ServiceExecutor implements Runnable {
   public void run() {
     try {
       while (!Thread.currentThread().isInterrupted()) {
-        Message msg = msgQueue.retrieveMsg();
+        var msg = msgQueue.retrieveMsg();
 
         if (null != msg) {
           LOGGER.info(msg.toString() + " is served.");

queue-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/TaskGenerator.java

@@ -63,12 +63,11 @@ public class TaskGenerator implements Task, Runnable {
    * submission TaskGenerator thread will sleep for 1 second.
    */
   public void run() {
-
-    int count = this.msgCount;
+    var count = this.msgCount;
 
     try {
       while (count > 0) {
-        String statusMsg = "Message-" + count + " submitted by " + Thread.currentThread().getName();
+        var statusMsg = "Message-" + count + " submitted by " + Thread.currentThread().getName();
         this.submit(new Message(statusMsg));
 
         LOGGER.info(statusMsg);