Basics

Question 1

What is Java?

Answer 1

Java is an OOP language based on C and managed by Oracle.

Question 2

Why do we use Java? (Advantages)

Answer 2

1. Java is platform independent (Write Once, Run Anywhere)
2. It is widely used and grandfathered in
3. Has a rich API( list of libraries) and documentation
4. It is open source
5. Easy to use, strongly typed

Question 3

What is the JDK, JRE, & JVM?

Answer 3

Java Development Kit(JDK): It is a tool used by developers to write source code, and it includes the JRE, JVM, debugger, devtools, e.t.c

Java Runtime Environment (JRE): is the collections of libraries required to help our program function/to run our java code. It contains the JVM.

Java Virtual Machine(JVM): it acts as an interpreter translating your java files into something your OS can understand.

Question 4

What is an Object?

Answer 4

An object is an instance of a class that has state (variables/attributes) and behavior(methods).

Question 5

What is a class?

Answer 5

A class is a blueprint/template for an object.

Question 6

What is OOP?

Answer 6

Object Oriented Programming is a way to utilize objects to represent our code in the real world

Question 7

What are the pillars of OOP?

Answer 7

A PIE
Abstraction
Polymorphism
Inheritance
Encapsulation

Question 8

What is Abstraction?

Answer 8

Abstraction is a technique used to hide HOW a thing works, but just showing WHAT it does. E.g: We know a remote changes the channel we just don’t care about how it works.

Question 9

What is Polymorphism?

Answer 9

Polymorphism is the ability of an entity to act/behave differently depending on the scenario/stimuli. E.g: water can act differently depending on the temp or container

Question 10

What is Inheritance?

Answer 10

Inheritance is the passing of attributes/behaviors from one entity to another. E.g: you get your parents DNA

Question 11

What is encapsulation?

Answer 11

Encapsulation is hiding/restricting direct access from users to sensitive information. Created by making methods private, and using getters and setters (accessors and mutators)

Question 12

What is the main method?

Answer 12

The entry point to our program. It is defined as

public static void main(String[] args){ }

Question 13

What is self documenting code?

Answer 13

Self document code is code that describes what it does via its own name. For example, naming your variables
something like “numOfInstances” instead of “x”

Question 14

What is a primitive data type?

Answer 14

It is a value that is not a referenced type. We don’t create new instances in the heap and they are stored on the call stack.

Question 15

What are the primitive data type?

Answer 15

boolean, int, char, float, double, byte, long

Question 16

What is flow control?

Answer 16

Flow control operators are a series of tools that help us control the ORDER of execution.
Without any flow control tools, the program reads the main method from top to bottom then exits.

Question 17

What are some tools we have available to us for flow control?

Answer 17

• -if, else, else if
  * -switch & case
  * -ternary
  * -while, dowhile, for, foreach/enhanced for loop

branching flow:

	 * -break & continue
	 * -try, catch, finally