Add Livelock example

Author: andrei-punko

build.gradle

@@ -84,4 +84,5 @@ tasks.register('githubWorkflowTest', Test) {
     exclude '**/**AddMultithreadingTest.class'
     exclude '**/**BlockingQueueTest.class'
     exclude '**/**DeadlockTest.class'
+    exclude '**/**LivelockTest.class'
 }

src/main/java/by/andd3dfx/multithreading/Deadlock.java

@@ -3,7 +3,7 @@
 import lombok.AllArgsConstructor;
 
 /**
- * <a href="http://docs.oracle.com/javase/tutorial/essential/concurrency/deadlock.html">Example</a> from JDK
+ * Taken from <a href="http://docs.oracle.com/javase/tutorial/essential/concurrency/deadlock.html">JDK docs</a>
  *
  * @see <a href="https://youtu.be/xuWU_6JTXi4">Video solution</a>
  */

src/main/java/by/andd3dfx/multithreading/Livelock.java

@@ -0,0 +1,79 @@
+package by.andd3dfx.multithreading;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.Setter;
+
+/**
+ * Taken from <a href="https://github.com/proselytear/javaconcurrency">this repo</a>
+ */
+public class Livelock {
+
+    @Getter
+    @Setter
+    @AllArgsConstructor
+    public static class Spoon {
+        private Eater owner;
+
+        public synchronized void use() {
+            System.out.printf("%s has eaten!", owner.getName());
+        }
+    }
+
+    @Getter
+    public static class Eater {
+        private String name;
+        private boolean isHungry;
+
+        public Eater(String n) {
+            name = n;
+            isHungry = true;
+        }
+
+        public void eatWith(Spoon spoon, Eater spouse) {
+            while (isHungry) {
+                // Don't have the spoon, so wait patiently for spouse.
+                if (spoon.getOwner() != this) {
+                    try {
+                        Thread.sleep(10);
+                    } catch (InterruptedException e) {
+                        continue;
+                    }
+                    continue;
+                }
+
+                // If spouse is hungry, insist upon passing the spoon.
+                if (spouse.isHungry()) {
+                    System.out.printf(
+                            "%s: You eat first my darling %s!%n",
+                            name, spouse.getName());
+                    spoon.setOwner(spouse);
+                    continue;
+                }
+
+                // Spouse wasn't hungry, so finally eat
+                spoon.use();
+                isHungry = false;
+                System.out.printf(
+                        "%s: I am stuffed, my darling %s!%n",
+                        name, spouse.getName());
+                spoon.setOwner(spouse);
+            }
+        }
+    }
+
+    public void makeLivelock() {
+        Eater husband = new Eater("Bob");
+        Eater wife = new Eater("Alice");
+
+        Spoon s = new Spoon(husband);
+
+        Thread thread1 = new Thread(() -> husband.eatWith(s, wife));
+        Thread thread2 = new Thread(() -> wife.eatWith(s, husband));
+
+        thread1.start();
+        thread2.start();
+
+        while (thread1.isAlive() || thread2.isAlive()) ;
+    }
+}

src/test/java/by/andd3dfx/multithreading/LivelockTest.java

@@ -0,0 +1,33 @@
+package by.andd3dfx.multithreading;
+
+import org.junit.Test;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+
+import static org.junit.Assert.assertFalse;
+
+public class LivelockTest {
+
+    @Test
+    public void makeLivelock() throws InterruptedException {
+        CompletableFuture<Void> future = CompletableFuture.supplyAsync(() -> {
+            new Livelock().makeLivelock();
+            return null;
+        });
+
+        new Thread(() -> {
+            try {
+                future.get();
+                System.out.println("Future completed!");
+            } catch (InterruptedException | ExecutionException e) {
+                throw new RuntimeException(e);
+            }
+        }).start();
+
+        // Wait 1 sec
+        Thread.sleep(1000);
+
+        assertFalse("Should not be completed after 1 sec wait", future.isDone());
+    }
+}