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);

queue-load-leveling/src/test/java/com/iluwatar/queue/load/leveling/AppTest.java

@@ -25,15 +25,12 @@ package com.iluwatar.queue.load.leveling;
 
 import org.junit.jupiter.api.Test;
 
-import java.io.IOException;
-
 /**
  * Application Test
  */
 public class AppTest {
   @Test
-  public void test() throws IOException {
-    String[] args = {};
-    App.main(args);
+  public void test() {
+    App.main(new String[]{});
   }
 }

queue-load-leveling/src/test/java/com/iluwatar/queue/load/leveling/MessageQueueTest.java

@@ -23,25 +23,23 @@
 
 package com.iluwatar.queue.load.leveling;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import org.junit.jupiter.api.Test;
+
 /**
- * 
  * Test case for submitting and retrieving messages from Blocking Queue.
- * 
  */
 public class MessageQueueTest {
 
   @Test
   public void messageQueueTest() {
-    
-    MessageQueue msgQueue = new MessageQueue();
-    
+
+    var msgQueue = new MessageQueue();
+
     // submit message
     msgQueue.submitMsg(new Message("MessageQueue Test"));
-    
+
     // retrieve message
     assertEquals("MessageQueue Test", msgQueue.retrieveMsg().getMsg());
   }

queue-load-leveling/src/test/java/com/iluwatar/queue/load/leveling/MessageTest.java

@@ -23,23 +23,21 @@
 
 package com.iluwatar.queue.load.leveling;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import org.junit.jupiter.api.Test;
+
 /**
- * 
  * Test case for creating and checking the Message.
- * 
  */
 public class MessageTest {
-  
+
   @Test
   public void messageTest() {
-    
+
     // Parameterized constructor test.
-    String testMsg = "Message Test";
-    Message msg = new Message(testMsg);
+    var testMsg = "Message Test";
+    var msg = new Message(testMsg);
     assertEquals(testMsg, msg.getMsg());
   }
 }

queue-load-leveling/src/test/java/com/iluwatar/queue/load/leveling/TaskGenSrvExeTest.java

@@ -26,25 +26,23 @@ package com.iluwatar.queue.load.leveling;
 import org.junit.jupiter.api.Test;
 
 /**
- * 
- * Test case for submitting Message to Blocking Queue by TaskGenerator
- * and retrieve the message by ServiceExecutor.
- * 
+ * Test case for submitting Message to Blocking Queue by TaskGenerator and retrieve the message by
+ * ServiceExecutor.
  */
 public class TaskGenSrvExeTest {
 
   @Test
   public void taskGeneratorTest() {
-    MessageQueue msgQueue = new MessageQueue();
-    
+    var msgQueue = new MessageQueue();
+
     // Create a task generator thread with 1 job to submit.
-    Runnable taskRunnable = new TaskGenerator(msgQueue, 1);
-    Thread taskGenThr = new Thread(taskRunnable);
+    var taskRunnable = new TaskGenerator(msgQueue, 1);
+    var taskGenThr = new Thread(taskRunnable);
     taskGenThr.start();
-    
+
     // Create a service executor thread.
-    Runnable srvRunnable = new ServiceExecutor(msgQueue);
-    Thread srvExeThr = new Thread(srvRunnable);
+    var srvRunnable = new ServiceExecutor(msgQueue);
+    var srvExeThr = new Thread(srvRunnable);
     srvExeThr.start();
   }