Merge pull request Beerkay#1 from IOAyman/master

 deleted some of the unnecessary code blocks, code is styled and  by IOAyman

JavaMultiThreadingCodes/src/CallableAndFuture_13/CallableTester.java

@@ -18,7 +18,7 @@
  * Runnable Introduced in Java 1.0 Callable<T> Introduced in Java 1.5 as part of
  * java.util.concurrent library
  *
- * Runnable cannot be parameterized Callable is a parameterized type whose type
+ * Runnable cannot be parametrized Callable is a parametrized type whose type
  * parameter indicates the return type of its run method Classes implementing
  *
  * Runnable needs to implement run() method, classes implementing Callable needs

JavaMultiThreadingCodes/src/CountDownLatch_6/App.java

@@ -5,30 +5,34 @@
 import java.util.concurrent.Executors;
 
 /**
- * CountDownLatch Java class to synchronize your threads’ activities.
- *
+ * {@link java.util.concurrent.CountDownLatch} Java class to synchronize your threads’ activities.
+ * <br><br>
  * Source:
- * (http://stackoverflow.com/questions/17827022/what-is-countdown-latch-in-java-multithreading)
+ * <em>http://stackoverflow.com/questions/17827022/what-is-countdown-latch-in-java-multithreading</em><br>
+ *
  * Any thread, usually main thread of application, which calls
- * CountDownLatch.await() will wait until count reaches zero or its interrupted
+ * {@link java.util.concurrent.CountDownLatch#await()} will wait until count reaches zero or its interrupted
  * by another thread. All other thread are required to do count down by calling
- * CountDownLatch.countDown() once they are completed or ready.
- *
+ * {@link java.util.concurrent.CountDownLatch#countDown()} once they are completed or ready.
+ * <br>
  * As soon as count reaches zero, Thread awaiting starts running. One of the
- * disadvantage of CountDownLatch is that its not reusable once count reaches to
- * zero you can not use CountDownLatch any more.
- *
- * Use CountDownLatch when one thread like main thread, require to wait for one
- * or more thread to complete, before it can start processing.
- *
- * Classical example of using CountDownLatch in Java is any server side core
- * Java application which uses services architecture, where multiple services
+ * disadvantage of {@link java.util.concurrent.CountDownLatch} is that it's
+ * not reusable once the count reaches to
+ * zero you can not use {@link java.util.concurrent.CountDownLatch} any more.
+ * <br><br>
+ * Use {@link java.util.concurrent.CountDownLatch} when one thread, like main
+ * thread, require to wait for one or more threads to complete, before it can
+ * start processing.
+ * <br><br>
+ * Classical example of using {@link java.util.concurrent.CountDownLatch} in
+ * Java is any server side core  Java application which uses services
+ * architecture, where multiple services
  * are provided by multiple threads and application can not start processing
  * until all services have started successfully.
- *
- * Codes with minor comments are from http://www.caveofprogramming.com/youtube/
+ * <br><br>
+ * Codes with minor comments are from <em>http://www.caveofprogramming.com/youtube/</em><br>
  * also freely available at
- * https://www.udemy.com/java-multithreading/?couponCode=FREE
+ * <em>https://www.udemy.com/java-multithreading/?couponCode=FREE</em>
  *
  * @author Z.B. Celik <[email protected]>
  */
@@ -45,10 +49,7 @@ public void run() {
 
         try {
             Thread.sleep(3000);
-        } catch (InterruptedException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        }
+        } catch (InterruptedException ignored) {}
         latch.countDown();
     }
 }
@@ -61,8 +62,10 @@ public static void main(String[] args) {
         for (int i = 0; i < 3; i++) {
             executor.submit(new Processor(latch));
         }
+        executor.shutdown();
+
         try {
-            // Application’s main thread waits, till other service threads which are 
+            // Application’s main thread waits, till other service threads which are
             // as an example responsible for starting framework services have completed started all services.
             latch.await();
         } catch (InterruptedException e) {

JavaMultiThreadingCodes/src/Deadlock_11/Runner.java

@@ -53,7 +53,7 @@ private void acquireLocks(Lock firstLock, Lock secondLock) throws InterruptedExc
         }
     }
 
-    //firstThreaad runs
+    //firstThread runs
     public void firstThread() throws InterruptedException {
         Random random = new Random();
         for (int i = 0; i < 10000; i++) {

JavaMultiThreadingCodes/src/Deadlock_11/SimpleDeadLock.java

@@ -10,8 +10,8 @@
  */
 public class SimpleDeadLock {
 
-    public static Object lock1 = new Object();
-    public static Object lock2 = new Object();
+    public static final Object lock1 = new Object();
+    public static final Object lock2 = new Object();
     private int index;
 
     public static void main(String[] a) {
@@ -28,7 +28,7 @@ public void run() {
                 System.out.println("Thread 1: Holding lock 1...");
                 try {
                     Thread.sleep(10);
-                } catch (InterruptedException e) {
+                } catch (InterruptedException ignored) {
                 }
                 System.out.println("Thread 1: Waiting for lock 2...");
                 synchronized (lock2) {
@@ -45,7 +45,7 @@ public void run() {
                 System.out.println("Thread 2: Holding lock 2...");
                 try {
                     Thread.sleep(10);
-                } catch (InterruptedException e) {
+                } catch (InterruptedException ignored) {
                 }
                 System.out.println("Thread 2: Waiting for lock 1...");
                 synchronized (lock1) {

JavaMultiThreadingCodes/src/InterruptingThreads14/App.java

@@ -31,9 +31,9 @@ public static void main(String[] args) throws InterruptedException {
 
         System.out.println("Starting.");
 
-        ExecutorService executer = Executors.newCachedThreadPool();
+        ExecutorService executor = Executors.newCachedThreadPool();
 
-        Future<?> fu = executer.submit(new Callable<Void>() {
+        Future<?> fu = executor.submit(new Callable<Void>() {
 
             @Override
             public Void call() throws Exception {
@@ -49,11 +49,11 @@ public Void call() throws Exception {
             }
         });
 
-        executer.shutdown();
+        executor.shutdown();
         Thread.sleep(500);
-        executer.shutdownNow();
+        executor.shutdownNow();
 
-        executer.awaitTermination(1, TimeUnit.DAYS);
+        executor.awaitTermination(1, TimeUnit.DAYS);
         System.out.println("Finished.");
     }
 

JavaMultiThreadingCodes/src/JoiningAndSynchronizeThreads_3/Worker.java

@@ -4,12 +4,12 @@
 import java.util.logging.Logger;
 
 /**
- * synchronized ("only let one thread in here at a time".) and join ("wait until
+ * {@code synchronized} ("only let one thread in here at a time".) and {@code join} ("wait until
  * thread on which join has called finished") keyword.
- *
- * Codes with minor comments are from http://www.caveofprogramming.com/youtube/
+ * <br><br>
+ * Codes with minor comments are from <em>http://www.caveofprogramming.com/youtube/</em><br>
  * also freely available at
- * https://www.udemy.com/java-multithreading/?couponCode=FREE
+ * <em>https://www.udemy.com/java-multithreading/?couponCode=FREE</em>
  *
  * @author Z.B. Celik <[email protected]>
  */
@@ -70,10 +70,7 @@ public void run() {
         try {
             thread1.join();
             thread2.join();
-        } catch (InterruptedException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        }
+        } catch (InterruptedException ignored) {}
         System.out.println("Count is: " + count);
     }
 }

JavaMultiThreadingCodes/src/LockObjects_4/App.java

@@ -1,9 +1,9 @@
 package LockObjects_4;
 
 /**
- * Codes with minor comments are from http://www.caveofprogramming.com/youtube/
+ * Codes with minor comments are from <em>http://www.caveofprogramming.com/youtube/</em><br>
  * also freely available at
- * https://www.udemy.com/java-multithreading/?couponCode=FREE
+ * <em>https://www.udemy.com/java-multithreading/?couponCode=FREE</em>
  *
  * @author Z.B. Celik <[email protected]>
  */

JavaMultiThreadingCodes/src/LockObjects_4/Worker.java

@@ -21,11 +21,11 @@ public class Worker {
 
     private Random random = new Random();
 
-    private Object lock1 = new Object();
-    private Object lock2 = new Object();
+    private final Object lock1 = new Object();
+    private final Object lock2 = new Object();
 
-    private List<Integer> list1 = new ArrayList<Integer>();
-    private List<Integer> list2 = new ArrayList<Integer>();
+    private List<Integer> list1 = new ArrayList<>();
+    private List<Integer> list2 = new ArrayList<>();
 
     public void stageOne() {
 

JavaMultiThreadingCodes/src/LockObjects_4/WorkerMethodsSynchronized.java

@@ -21,8 +21,8 @@ public class WorkerMethodsSynchronized {
 
     private Random random = new Random();
 
-    private List<Integer> list1 = new ArrayList<Integer>();
-    private List<Integer> list2 = new ArrayList<Integer>();
+    private List<Integer> list1 = new ArrayList<>();
+    private List<Integer> list2 = new ArrayList<>();
 
     /**
      * synchronized, methods use different data (list1 list2) so by synchronized
@@ -78,10 +78,7 @@ public void run() {
         try {
             t1.join();
             t2.join();
-        } catch (InterruptedException e) {
-            // TODO Auto-generated catch block
-            e.printStackTrace();
-        }
+        } catch (InterruptedException ignored) {}
 
         long end = System.currentTimeMillis();
 

JavaMultiThreadingCodes/src/LowLevelProducerConsumer_9/App.java

@@ -1,15 +1,16 @@
 package LowLevelProducerConsumer_9;
 
 /**
- * How to implement the producer-consumer pattern using "low level" techniques;
+ * How to implement the Producer-Consumer pattern using "low level" techniques;
  * namely, wait, notify and synchronized. This isn't the best way to implement a
- * producer-consumer pattern in Java (see tutorial 7 use of BlockingQueue for
+ * Producer-Consumer pattern in Java
+ * (see tutorial 7 use of {@link java.util.concurrent.BlockingQueue} for
  * the best way); but this tutorial will help you to understand how to use wait
  * and notify.
- *
- * Codes with minor comments are from http://www.caveofprogramming.com/youtube/
+ * <br><br>
+ * Codes with minor comments are from <em>http://www.caveofprogramming.com/youtube/</em><br>
  * also freely available at
- * https://www.udemy.com/java-multithreading/?couponCode=FREE
+ * <em>https://www.udemy.com/java-multithreading/?couponCode=FREE</em>
  *
  * @author Z.B. Celik <[email protected]>
  */
@@ -22,9 +23,7 @@ public static void main(String[] args) throws InterruptedException {
             public void run() {
                 try {
                     processor.produce();
-                } catch (InterruptedException e) {
-                    e.printStackTrace();
-                }
+                } catch (InterruptedException ignored) {}
             }
         });
 
@@ -33,14 +32,18 @@ public void run() {
             public void run() {
                 try {
                     processor.consume();
-                } catch (InterruptedException e) {
-                    e.printStackTrace();
-                }
+                } catch (InterruptedException ignored) {}
             }
         });
+
         t1.start();
         t2.start();
-        t1.join();
-        t2.join();
+//        t1.join();
+//        t2.join();
+
+        // Pause for 30 seconds and force quitting the app (because we're
+        // looping infinitely)
+        Thread.sleep(30000);
+        System.exit(0);
     }
 }

JavaMultiThreadingCodes/src/LowLevelProducerConsumer_9/Processor.java

@@ -1,26 +1,27 @@
 package LowLevelProducerConsumer_9;
 
 /**
- * Codes with minor comments are from http://www.caveofprogramming.com/youtube/
+ * Codes with minor comments are from <em>http://www.caveofprogramming.com/youtube/</em><br>
  * also freely available at
- * https://www.udemy.com/java-multithreading/?couponCode=FREE
+ * <em>https://www.udemy.com/java-multithreading/?couponCode=FREE</em>
  *
  * @author Z.B. Celik <[email protected]>
  */
 import java.util.LinkedList;
 import java.util.Random;
 
+@SuppressWarnings("InfiniteLoopStatement")
 public class Processor {
 
     private LinkedList<Integer> list = new LinkedList<>();
     private final int LIMIT = 10;
-    private Object lock = new Object();
+    private final Object lock = new Object();
 
     public void produce() throws InterruptedException {
         int value = 0;
         while (true) {
             synchronized (lock) {
-                //whenever the threade is notofied starts again from the loop
+                //whenever the thread is notified starts again from the loop
                 while (list.size() == LIMIT) {
                     lock.wait();// wait() is also true
                 }