Add async samples

async/src/main/java/threadexamples/producerconsumer/App.java

@@ -21,7 +21,7 @@ public class App {
         for (int i = 0; i < 3; i++) {
             final Consumer consumer = new Consumer("Consumer_" + i, itemQueue);
             executorService.submit(() -> {
-                while(true) {
+                while (true) {
                     consumer.consume();
                 }
             });

async/src/main/java/threadexamples/producerconsumer/Consumer.java

@@ -5,7 +5,7 @@ import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.BlockingQueue;
 
-public class Consumer {
+class Consumer {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(Consumer.class);
 
@@ -13,12 +13,12 @@ public class Consumer {
     private String name;
     private int itemId;
 
-    public Consumer(String name, BlockingQueue<Item> itemQueue) {
+    Consumer(String name, BlockingQueue<Item> itemQueue) {
         this.itemQueue = itemQueue;
         this.name = name;
     }
 
-    public void consume() throws InterruptedException {
+    void consume() throws InterruptedException {
         final Item item = itemQueue.take();
         LOGGER.info("Consumer [{}] consume item [{}] produced by [{}]", name, item.getId(), item.getProducer());
     }

async/src/main/java/threadexamples/producerconsumer/Item.java

@@ -1,20 +1,20 @@
 package threadexamples.producerconsumer;
 
-public class Item {
+class Item {
 
     private String producer;
     private int id;
 
-    public Item(String producer, int id) {
+    Item(String producer, int id) {
         this.producer = producer;
         this.id = id;
     }
 
-    public String getProducer() {
+    String getProducer() {
         return producer;
     }
 
-    public int getId() {
+    int getId() {
         return id;
     }
 

async/src/main/java/threadexamples/producerconsumer/Producer.java

@@ -3,18 +3,18 @@ package threadexamples.producerconsumer;
 import java.util.Random;
 import java.util.concurrent.BlockingQueue;
 
-public class Producer {
+class Producer {
 
     private BlockingQueue<Item> itemQueue;
     private String name;
     private int itemId;
 
-    public Producer(String name, BlockingQueue itemQueue) {
+    Producer(String name, BlockingQueue<Item> itemQueue) {
         this.itemQueue = itemQueue;
         this.name = name;
     }
 
-    public void produce() throws InterruptedException {
+    void produce() throws InterruptedException {
         itemQueue.put(new Item(name, itemId++));
         Thread.sleep(new Random().nextInt(2000));
     }