Refactor notes and README.md

Author: abhinav-nath

README.md

@@ -1,25 +1,32 @@
 # Multithreading and Concurrency in Java
 
-All about Multi-threading and Concurrent programming in Java. Simple and easy to understand code examples for most of the Concurrent APIs provided by Java.
+All about Multi-threading and Concurrent programming in Java.
+Simple and easy to understand code examples for most of the Concurrent APIs provided by Java.
 
 #### All about Threads
 - [Motivation - Why do we need Threads?](./notes/threads-motivation.md)
 - [Threads in Java](./src/com/codecafe/concurrency/thread)
-  - [Creating Threads](./src/com/codecafe/concurrency/thread/basics/designathread/creating-threads.md)
-  - [Thread States](./src/com/codecafe/concurrency/thread/basics/designathread/thread-states.md)
+  - [Creating Threads](./notes/creating-threads.md) using
+    - [Runnable](./src/com/codecafe/concurrency/thread/basics/designathread/ThreadDemo.java)
+    - [Thread class](./src/com/codecafe/concurrency/thread/basics/designathread/ThreadDemo.java)
+    - [Callable](./src/com/codecafe/concurrency/thread/basics/designathread/CallableDemo.java)
+    - [ExecutorService](notes/executorservice.md) - [[code](./src/com/codecafe/concurrency/executorservice/ExecutorServiceDemo.java)]
+  - [Thread States](./notes/thread-states.md) - [[code](./src/com/codecafe/concurrency/thread/basics/designathread/ThreadStates.java)]
+  - [Stop a Thread](./src/com/codecafe/concurrency/thread/basics/StopAThreadInMiddle.java)
 - [Thread Signalling](./src/com/codecafe/concurrency/threadsignalling)
-- [Daemon Thread](./src/com/codecafe/concurrency/thread/daemonthread/daemon-thread.md)
+- [Daemon Thread](./notes/daemon-thread.md) - [[code](./src/com/codecafe/concurrency/thread/daemonthread)]
 
 #### Thread synchronization and locks
 - [The `synchronized` keyword](./src/com/codecafe/concurrency/_synchronized)
 - [Locks](./src/com/codecafe/concurrency/locks)
 - [Deadlock](./src/com/codecafe/concurrency/deadlock)
 
 #### Concurrent APIs provided by Java
-- [ExecutorService](./src/com/codecafe/concurrency/executorservice/executorservice.md)
 - [BlockingQueue](./src/com/codecafe/concurrency/blockingqueue)
-- [Semaphore](./src/com/codecafe/concurrency/semaphore/semaphore.md)
-- [CountdownLatch](./src/com/codecafe/concurrency/countdownlatch/countdownlatch.md)
-- [CyclicBarrier](./src/com/codecafe/concurrency/cyclicbarrier/cyclicbarrier.md)
+- [Semaphore](./notes/semaphore.md) - [[code](./src/com/codecafe/concurrency/semaphore)]
+- [CountdownLatch](./notes/countdownlatch.md) - [[code](./src/com/codecafe/concurrency/countdownlatch/CountDownLatchDemo.java)]
+  - [with time-out](./src/com/codecafe/concurrency/countdownlatch/timeout/TerminatingCountDownLatch.java)
+- [CyclicBarrier](./notes/cyclicbarrier.md) - [[code](./src/com/codecafe/concurrency/cyclicbarrier/CyclicBarrierDemo.java)]
+  - [Need of CyclicBarrier](./src/com/codecafe/concurrency/cyclicbarrier/NeedOfCyclicBarrier.java)
 - [`atomic` variables](./src/com/codecafe/concurrency/_atomic)
-- [The `volatile` keyword](./src/com/codecafe/concurrency/_volatile/volatile-keyword.md)
+- [The `volatile` keyword](./src/com/codecafe/concurrency/_volatile/volatile-keyword.md) - [[code](./src/com/codecafe/concurrency/_volatile/VolatileDemo.java)]

src/com/codecafe/concurrency/java_memory_model.png renamed to images/java_memory_model.png

@@ -1,9 +1,11 @@
 ## Motivation - Why do we need Threads?
 
-1. **[Responsiveness](#responsiveness---concurrency)**
-2. **[Performance](#performance---parallelism)**
+For two primary things:
 
-## Responsiveness - Concurrency
+1. **[Responsiveness](#responsiveness---achieved-by-concurrency)**
+2. **[Performance](#performance---achieved-by-parallelism)**
+
+## Responsiveness - achieved by Concurrency
 
 ### Examples of Poor Responsiveness
 
@@ -22,7 +24,7 @@ The term we use for this kind of multi-tasking is **concurrency**.
 
 We don't need multiple cores to achieve concurrency. Even with one core, we can create responsive applications by using multiple threads.
 
-## Performance - Parallelism
+## Performance - achieved by Parallelism
 
 - We can create an *illusion* of multiple tasks executing in parallel using just a single core.
 - With **multiple cores**, we can truly run tasks completely in parallel.

src/com/codecafe/concurrency/countdownlatch/countdownlatch.md renamed to notes/countdownlatch.md

@@ -7,7 +7,7 @@ public void run() {
     for (; ; ) {
       // Returns true if the thread is interrupted
       if (interrupted()) {
-        // You are supposed to rollback or reverse the operation in progress and stop
+        // You are supposed to roll back or reverse the operation in progress and stop
         System.out.println("Thread is interrupted hence stopping...");
         // Terminates the loop
         break;

src/com/codecafe/concurrency/thread/basics/designathread/creating-threads.md renamed to notes/creating-threads.md

@@ -1,10 +1,6 @@
 package com.codecafe.concurrency.thread.basics.designathread;
 
-import java.util.concurrent.Callable;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
+import java.util.concurrent.*;
 
 class MyMath {
   public static int add(int a, int b) {
@@ -28,6 +24,7 @@ public Integer call() throws Exception {
     int result = x + y;
     return result;
   }
+
 }
 
 public class CallableDemo {