Java 11 migrate remaining p (#1122)

* Moves partial-response to Java 11

* Moves pipeline to Java 11

* Moves poison-pill to Java 11

* Moves priority-queue to Java 11

* Moves private-class-data to Java 11

* Moves producer-consumer to Java 11

* Moves promise to Java 11

* Moves property to Java 11

* Moves prototype to Java 11

* Moves proxy to Java 11

* Corrects checkstyle errors

* Fixes build for pipeline pattern

poison-pill/src/main/java/com/iluwatar/poison/pill/App.java

@@ -42,26 +42,18 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) {
-    MessageQueue queue = new SimpleMessageQueue(10000);
+    var queue = new SimpleMessageQueue(10000);
 
-    final Producer producer = new Producer("PRODUCER_1", queue);
-    final Consumer consumer = new Consumer("CONSUMER_1", queue);
+    final var producer = new Producer("PRODUCER_1", queue);
+    final var consumer = new Consumer("CONSUMER_1", queue);
 
-    new Thread() {
-      @Override
-      public void run() {
-        consumer.consume();
-      }
-    }.start();
+    new Thread(consumer::consume).start();
 
-    new Thread() {
-      @Override
-      public void run() {
-        producer.send("hand shake");
-        producer.send("some very important information");
-        producer.send("bye!");
-        producer.stop();
-      }
-    }.start();
+    new Thread(() -> {
+      producer.send("hand shake");
+      producer.send("some very important information");
+      producer.send("bye!");
+      producer.stop();
+    }).start();
   }
 }

poison-pill/src/main/java/com/iluwatar/poison/pill/Consumer.java

@@ -47,22 +47,20 @@ public class Consumer {
    */
   public void consume() {
     while (true) {
-      Message msg;
       try {
-        msg = queue.take();
+        var msg = queue.take();
         if (Message.POISON_PILL.equals(msg)) {
           LOGGER.info("Consumer {} receive request to terminate.", name);
           break;
         }
+        var sender = msg.getHeader(Headers.SENDER);
+        var body = msg.getBody();
+        LOGGER.info("Message [{}] from [{}] received by [{}]", body, sender, name);
       } catch (InterruptedException e) {
         // allow thread to exit
         LOGGER.error("Exception caught.", e);
         return;
       }
-
-      String sender = msg.getHeader(Headers.SENDER);
-      String body = msg.getBody();
-      LOGGER.info("Message [{}] from [{}] received by [{}]", body, sender, name);
     }
   }
 }

poison-pill/src/main/java/com/iluwatar/poison/pill/Producer.java

@@ -57,7 +57,7 @@ public class Producer {
       throw new IllegalStateException(String.format(
           "Producer %s was stopped and fail to deliver requested message [%s].", body, name));
     }
-    Message msg = new SimpleMessage();
+    var msg = new SimpleMessage();
     msg.addHeader(Headers.DATE, new Date().toString());
     msg.addHeader(Headers.SENDER, name);
     msg.setBody(body);