Udacity Class Intro to Java Programming walkthrough, review, rating and notes

Intro to Java Programming
(This document is a work in progress. Please excuse its appearance)

• General comments:
• Video has occasional interviews of young female coders, role models - cs students from Stanford
• Lesson 1 - Introduction
• Tidying Legos : 
• Example: use lego swap, sorting, rearrangement as example of algorithm
• Example: calculation of dinner bill and tip is a good example of an algorithm
• Moving to the First Yellow-Blue Lego
• Exercise: really helpful exercise writing pseudo code and understanding algorithm
• Concept: Why is this not a correct algorithm? 01 description is ambiguous?  02 description contains steps that cannot be executed ? 03 procedure does not always terminate

Udacity Introduction to Java Programming
Move to the First Yellow-Blue

Example algorithm that does not terminate

• Problem set 0:
• Install BlueJ and look at folder files to find secret codes. Familiarize yourself with your programming environment
• Objects
• Concept - coders organize their code into objects
• Concept - can use objects already written by other people, stand on the should of the giants
• Concept - two important things to understand about objects: 01 what can an object do? 02 How to make the object do it?
• Why is OOP so important?
• Industry standard, job requirement to use object oriented programming
• Concept - a person is a perfect analogy of an object (computer science): a person has attributes / properties like height weight, and he/she is can do all kinds of things. OOP is intuitive - it is aligned with the way we think 
• Objects
• Analogy - objects are like appliances in a big house. Each appliance such as a heater or the washer has some build-in functionalities 
• Concept - Object = building block of a program, component with some desired functionality. You can ask objects to do work. 
• Concept - You don't necessarily know how they do that - how they complete each task. 
• Analogy - We don't know usually know the granular details how a heater works, as long as it heats water
• Concept - it's important to understand WHAT an object can do, NOT necessarily HOW it does that
• Lesson Title : Objects demo
• Exercise: learn to use an existing project, and start a new instance of an object
• Concept: It's important to not get hung up on how an object does its task exactly to the greatest details.  The amount of codes in each project can be overwhelming. It's important to follow instruction, and ignore the extra details. 
• Lesson Title: Lesson 2 - Objects - Classes
• Concept: in Java, class = objects with common behaviors. Example the day class, when you want to use objects in this class, look at its documentations. Example: the string class defines the common behavior of the string objects.
• Concept: methods = actions that can be done by a class
• Comments: this is a really good way to think about objects, for those who are new to OOP
• Lesson Title: Lesson 2 - Drawing Pictures
• Exercise: playing with interesting codes that can edit and modify pictures
• Comment: this is a great exercise, showcasing a real-world application of Java, and how powerful it is for image manipulation
• Lesson Title: Lesson 2 - Variable Names
• Concept - Use variable to store a value that you need to retrieve later. Every variable has a name. Analogy: parking lot spot, parking structure label

• Lesson 2 Objects An Exercise on Variable Names
• Identify the variable names in variable declarations
• Lesson 2 Objects Variables
• Concept Variable Type: in Java writes the type before the variable name. Analogy: parking spot for a bike, versus for motorbikes versus for a car. In Java, we have to specify which type of data the variable holds. 
• Concept Initial Value : when declaring a new variable, always best practice to specify an initial value. 
• Concept data type double: a number that can have a decimal point. Ignore the curious name. 
• Commonly seen types: string, double, int, and more
• Lesson 2 Objects Comments
• // double slash comments for humans to understand the code better
• "Comments are for humans (human readers)"
• Lesson 2 Objects Variable Declarations: The Fine Print
• Exercises: spot mistakes in variable declaration statements