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Author: abhinav-nath

README.md

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 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)

images/responsiveness.png

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+## Motivation - Why do we need Threads?
+
+1. **[Responsiveness](#responsiveness---concurrency)**
+2. **[Performance](#performance---parallelism)**
+
+## Responsiveness - Concurrency
+
+### Examples of Poor Responsiveness
+
+- Waiting for Customer Support
+- Late response from a person
+- No feedback from an application
+
+![Responsiveness](../images/responsiveness.png)
+
+- Responsiveness can be achieved by using multiple threads, with a separate thread for each task.
+- Generally very hard to achieve otherwise.
+
+> By multi-tasking quickly between threads, the CPU can create an illusion that all the tasks are executing at the same time.
+
+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
+
+- 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.
+
+**Performance - Impact**
+- Completing a complex task much faster
+- Finish more work in the same period of time
+- For high-scale services:
+  - Fewer machines
+  - Less money spent on hardware