Java Programming Concepts Quiz

Object Oriented Programming (OOP) Course Notes

• This course covers Object-Oriented Programming (OOP) concepts using Java.
• The recommended textbook is Java How to Program by Deitel & Deitel (9th Edition or 6th+ editions are acceptable).
• The course includes lectures on OOP history, concepts, and related Java applications.

Lecture 1

• OOP History: Alan Kay is considered a father of OOP concepts.
• OOP Concept: OOP uses "Objects" and their interactions to design applications and programs. This is a programming paradigm. OOP is an approach to program organization and development.
• Decomposition into Objects: OOP breaks a problem into entities called Objects, then builds Attributes (data/variables) and Methods (functions) around these entities.
• Problem vs. Solution Space: The program's problem space exists in the real world. The solution space for the program is on the computer.
• Object-Oriented Approach: Describe the problem in real-world terms, not in computer program terms.

Lecture 2

• Basic Structure of a Java Program: Every Java program needs at least one class. Each line of code must be inside a class. The class keyword introduces a class declaration, followed by the class name.
• General Syntax of Java Classes: class Name { // Attributes // Methods public static void main(String args[]) { //some statements } } The filename must match the class name and end with .java.
• Java Classes/Objects: Use the class keyword to define a Java class. An object is instance of a class. Classes are templates used to create multiple objects.
• Java Class Attributes: Attributes in a class are variables. Example in a class named "Main" with attributes int x; and int y;.
• Access to Attributes: Get attributes of a class by creating an object and using the dot syntax: myObj.x. You can set values of attributes as well.
• Java Constructor: A special method used for initializing objects, the constructor's name must match the class name and has no return type. All classes have a constructor, if you do not create one Java creates it for you.
• Java Packages: Packages in Java group related classes. The Java API is a library of pre-written classes, libraries in Java are divided into packages and classes. Import specific classes or packages (import java.util.Scanner;).

Lecture 3

• Java Methods: A method is a block of code run when called. Methods can take parameters (data/information). In OOP, methods/functions are used to perform specific actions.
• Why Use Methods for Code Re-use: Methods allow the re-use of code. Define the code once and use it many times.
• Method Requirements: Declared inside a class. Use method name, parentheses (())
• Java Methods Example: Inside a class Box use methods like void volume() to calculate the volume of a box using its member variables.

Lecture 4

• Java Modifiers: Modifiers control access to attributes and methods within a class (access modifiers). Modifiers also specify additional functional behavior (non-access modifiers). For example static indicates class-level not object-level and final indicates a class cannot be inherited.
• Access Modifiers (Example):
  • public: Accessible from any class.
  • default: Accessible only within the same package.
• Non-Access Modifiers(Example):
  • static: Belongs to class level not object level. Can be called without creating an object.
  • final: Prevents inheritance.

Lecture 5

• Basic Concepts: Encapsulation, Abstraction, Inheritance, Polymorphism.
• Encapsulation: The process of restricting access to data members and methods, allowing control.
• Abstraction: Show only essential details to the user and hide others.
• Getters (Accessors): Public methods to access private attributes (data).
• Setters (Mutators): Public methods to modify private attributes.

Lecture 6

• Java Abstraction: Hiding non-essential details of an implementation and only showing essential aspects for a user. Achieved using Interfaces or Abstract classes.
• Abstract Classes: Cannot create objects and use the abstract keyword for methods / functions without implementation. The methods need to be implemented in subclasses.
• Interfaces: Completely abstract classes used for methods grouping. Use implements. Interfaces can be implemented by multiple subclasses.

Lecture 7

• Inheritance: A relationship between classes where a subclass "inherits from" a superclass. The child class adopts attributes/methods from the parent class. Example: class Student extends Person { ... }
• Polymorphism: Creates many forms of a method that are related to each other but behave differently depending on which class object is calling it. For example, a print method in different classes will give different output.

Lecture 8

• Java Inheritance and multiple inheritance: Java does not support multiple inheritance directly. It is done through interfaces instead which results in fewer complexities.
• Super Method: When child class method overrides inherited method, you can access the method from the parent class using super.

Lecture 9

• Java Files: Java provides a File class which is used to handle files and directories. Using this class, you can check for files, make files or directories, and read/write files. Use of java.io and related exceptions often help with file handling.
• Create a File (example): File myFile = new File("myFile.txt").
• Delete a File (example): if(myFile.delete()) { ... }
• Write to a File (example): Use the PrintWriter class to write text data to a file.
• Read from a File (example): Use the Scanner class to read text data from a file and it will print the output to the console.

Test your knowledge on Java programming concepts including string manipulation, constructors, and immutability. This quiz covers key methods and features of the Java language to assess your understanding of fundamental principles. Prepare to challenge your Java skills and see how well you know this versatile programming language.