TOC aligned with title, question on null from General to Languages

Author: arialdomartini

README.md

@@ -79,6 +79,7 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
   * [Constructors and Interfaces](#constructors-and-interfaces)
   * [Node.js](#node-js)
   * [Java and Time Traveling](#java-and-time-traveling)
+  * [Eliminate Null](#eliminate-null)
 
 * [Web Questions](#web)
   * [3rd Party Cookies](#3rd-party-cookies)
@@ -113,7 +114,7 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
   * [Rebase](#rebase)
   * [Merging in HG and in Git](#merging-in-hg-and-in-git)
 
-* [Concurrency Questions](#concurrency)
+* [Questions about Concurrency](#concurrency)
   * [Why?](#why)
   * [Testing Concurrency](#testing-concurrency)
   * [Race Conditions](#race-conditions)
@@ -147,7 +148,7 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
   * [Team Organization](#team-organization)
   * [Turn Over](#turn-over)
   * [Qualities](#qualities)
-  * [3 Things about Code](#3-things-about-code)
+  * [3 Things About Code](#3-things-about-code)
   * [1 Month's Revolution](#1-months-revolution)
 
 * [Questions about logic and algorithms](#algorithms)
@@ -170,7 +171,7 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
   * [Event-Driven Architecture](#event-driven-architecture)
   * [Readibility](#readibility)
   * [Emergent and Evolutionary](#emergent-and-evolutionary)
-  * [ Scale-Out, Scale-Up](#scale-out-scale-up)
+  * [Scale-Out, Scale-Up](#scale-out-scale-up)
   * [Failures User Sessions](#failures-user-sessions)
   * [CQRS](#cqrs)
   * [n-tier](#n-tier)
@@ -199,9 +200,9 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
 
 * [Questions about Security](#security)
   * [Security by Default](#security-by-default)
-  * [Don't invent Cryptography](#dont-invent-cryptography)
+  * [Don't Invent Cryptography](#dont-invent-cryptography)
   * [2-FA](#2-fa)
-  * [Sensible Data in Logs](#sensible-data-in-logs)
+  * [Confidential Data in Logs](#confidential-data-in-logs)
   * [SQL Injection](#sql-injection)
   * [Detect SQL Injection](#detect-sql-injection)
   * [XSS](#xss)
@@ -224,14 +225,13 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
   * [TCP and HTTP](#tcp-and-http)
   * [Client-Side vs Server-Side](#client-side-vs-server-side)
   * [Reliable and non-reliable channels](#reliable-and-non-reliable-channels)
-  * [Million-Dollar Mistake](#million-dollar-mistake)
 
 * [Open Questions](#open)
   * [Resistance to Change](#resistance-to-change)
   * [Threading ELI5](#threading-eli5)
   * [Innovation and Predictability](#innovation-and-predictability)
   * [Good Code](#good-code)
-  * [Stradming](#stradming)
+  * [Streaming](#streaming)
   * [1 Week Improvement](#1-week-improvement)
   * [Learnt this week](#learnt-this-week)
   * [Aestheric](#aestheric)
@@ -240,7 +240,7 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
   * [Reinvent the Wheel](#reinvent-the-wheel)
   * [Not Invented Here](#not-invented-here)
   * [Next Thing to Automate](#next-thing-to-automate)
-  * [Code is Hard](#code-is-hard)
+  * [Coding is Hard](#coding-is-hard)
   * [Green Fields and Brown Fields](#green-fields-and-brown-fields)
   * [Type "Google.com"](#type-googlecom)
   * [While idle](#while-idle)
@@ -253,7 +253,7 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
   * [I'm proud of](#im-proud-of)
 
 * [Questions based on snippets of code](#snippets)
-  * [Beware the closure](#beware-the-closure)
+  * [Beware the Closure](#beware-the-closure)
   * [Type Erasure](#type-erasure)
   * [Memory Leak](#memory-leak)
   * [Kill the switch](#kill-the-switch)
@@ -276,7 +276,6 @@ Feel free to open a [Discussion](https://github.com/arialdomartini/Back-End-Deve
 
 
 ### [[↑]](#toc) <a name='patterns'>Questions about Design Patterns:</a>
-
 #### Globals Are Evil
 Why are global and static objects evil? Can you show it with a code example?
 
@@ -298,12 +297,14 @@ Active-Record is the design pattern that promotes objects to include functions s
 Data-Mapper is a design pattern that promotes the use of a layer of Mappers that moves data between objects and a database while keeping them independent of each other and the mapper itself. On the contrary, in Active-Record objects directly incorporate operations for persisting themselves to a database, and properties corresponding to the underlying database tables. Do you have an opinion on those patterns? When would you use one instead of the other?
 
 #### Billion Dollar Mistake
-Why is it often said that the introduction of `null` is a "billion dollar mistake"? Would you discuss the techniques to avoid it, such as the Null Object Pattern introduced by the GOF book, or Option types?
+[Tony Hoare](https://en.m.wikipedia.org/wiki/Tony_Hoare) who invented the null reference once said "*I call it my billion-dollar mistake*" since it led to "*innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years*".
+
+Would you discuss the techniques to avoid it, such as the Null Object Pattern introduced by the GOF book, or Option types?
 
 #### Inheritance vs Composition
 Many state that, in Object-Oriented Programming, composition is often a better option than inheritance. What's you opinion?
 
-#### Anti-corruption Layer
+#### Anti-Corruption Layer
 What is an Anti-corruption Layer?
 
 #### Singleton
@@ -339,7 +340,7 @@ Why do array indexes start with '0' in most languages?
 #### TDD
 How do tests and TDD influence code design?
 
-#### DRY violation
+#### DRY Violation
 Write a snippet of code violating the Don't Repeat Yourself (DRY) principle. Then, explain why it is a bad design, and fix it.
 
 #### Cohesion vs Coupling
@@ -348,7 +349,7 @@ What's the difference between cohesion and coupling?
 #### Refactoring
 What is refactoring useful for?
 
-#### Code comments
+#### Code Comments
 Are comments in code useful? Some say they should be avoided as much as possible, and hopefully made unnecessary. Do you agree?
 
 #### Design vs Architecture
@@ -363,7 +364,7 @@ C++ supports multiple inheritance, and Java allows a class to implement multiple
 #### Domain Logic in Stored Procedures
 What are the pros and cons of holding domain logic in Stored Procedures?
 
-#### OOP took over the world
+#### OOP Took Over the World
 In your opinion, why has Object-Oriented Design dominated the market for so many years?
 
 #### Bad Design
@@ -435,6 +436,8 @@ In the last years there has been a lot of hype around Node.js. What's your opini
 
 #### Java and time-traveling
 * Pretend you have a time machine and pretend that you have the opportunity to go to a particular point in time during Java's (or C#, Python, Go or whatever) history, and talk with some of the JDK architects. What would you try to convince them of? Removing checked exceptions? Adding unsigned primitives? Adding multiple-inheritance?
+#### Eliminate Null
+Imagine you want to remove the possibility to have null references in your preferred language: how would you achieve this goal? What consequences would this have?
 
 
 ### [[↑]](#toc) <a name='web'>Questions about Web development:</a>
@@ -680,7 +683,7 @@ What makes code readable?
 #### Emergent and Evolutionary
 What is the difference between emergent design and evolutionary architecture?
 
-##### Scale-Out, Scale-Up
+#### Scale-Out, Scale-Up
 Scale out vs scale up: how are they different? When to apply one, when the other?
 
 #### Failures User Sessions
@@ -761,13 +764,13 @@ What are the pros and cons of microservice architecture?
 #### Security by Default
 How do you write secure code? In your opinion, is it one of the developer's duties, or does it require a specialized role in the company? And why?
 
-#### Don't invent Cryptography
+#### Don't Invent Cryptography
 Why is it said that cryptography is not something you should try to invent or design yourself?
 
 #### 2-FA
 What is two factor authentication? How would you implement it in an existing web application?
 
-#### Sensible Data in Logs
+#### Confidential Data in Logs
 If not carefully handled, there is always a risk of logs containing sensitive information, such as passwords. How would you deal with this?
 
 #### SQL Injection
@@ -834,8 +837,6 @@ What are the tradeoffs of client-side rendering vs. server-side rendering?
 How could you develop a reliable communication protocol based on a non-reliable one?
 
 
-#### Million-Dollar Mistake
-[Tony Hoare](https://en.m.wikipedia.org/wiki/Tony_Hoare) who invented the null reference once said "*I call it my billion-dollar mistake*" since it led to "*innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years*". Imagine you want to remove the possibility to have null references in your preferred language: how would you achieve this goal? What consequences could this have?
 
 
 ### [[↑]](#toc) <a name='open'>Open Questions:</a>
@@ -852,7 +853,7 @@ As a software engineer you want both to innovate and to be predictable. How thos
 #### Good Code
 What makes good code good?
 
-#### Stradming
+#### Streaming
 Explain streaming and how you would implement it.
 
 #### 1 Week Improvement
@@ -878,7 +879,7 @@ Let's have a conversation about "*reinventing the wheel*", the "*not invented he
 
 #### Next Thing to Automate
 What's the next thing you would automate in your current workflow?
-#### Code is Hard
+#### Coding is Hard
 Why is writing software difficult? What makes maintaining software hard?
 
 #### Green Fields and Brown Fields
@@ -915,7 +916,7 @@ What have you achieved recently that you are proud of?
 
 ### [[↑]](#toc) <a name='snippets'>Questions about snippets of code:</a>
 
-#### Beware the closure
+#### Beware the Closure
 What's the output of this Javascript function?
 ```javascript
 function hookupevents() {
@@ -971,7 +972,7 @@ public class Stack {
 }
 ```
 
-#### Kill the switch
+#### Kill the wwitch
 `if`s and in general conditional statements lead to procedural and imperative programming. Can you get rid of this `switch` and make this snippet more object oriented?
 
 ```java