Java Course Notes

Instructor Introduction

• Mosh will be the instructor.
• Course contents include:
  • Installing necessary tools for Java.
  • Basics of Java programming.
  • Building algorithms and writing professional-quality code.
• Designed for beginners.

Instructor Background

• Mosh: Software engineer with 20 years of experience.
• Over 3 million people taught to code.
• Owns a coding school called "Code with Mosh."

Course Overview

Tools Installation

1. Java Development Kit (JDK)

   • Search for "JDK download."
   • Accept license agreement and download the appropriate version for your OS (Windows, Mac, Linux).
   • Install JDK.

2. Code Editor

   • Recommended: IntelliJ IDEA (Community edition)
   • Alternatives: NetBeans, Eclipse.
   • Drag and drop IntelliJ into Applications folder.

Anatomy of a Java Program

• Functions: Building blocks in Java.
  • Block of code that performs a task.
  • Example functions: Sending emails, validating input.

Creating Functions

• Start with return type (e.g., void).
• Function name should be descriptive (e.g., sendEmail).
• Curly braces {} define code block.
• Main function is public static void main(String[] args) (entry point of every Java application).

Class Structure

• Classes: Containers for related functions (methods).
  • At least one class must contain the main function.
  • Use access modifiers: public, private, etc.

Naming Conventions

• Pascal case for classes (First letter of each word is uppercase).
• Camel case for methods (First letter of the first word is lowercase, first letter of subsequent words is uppercase).

Writing Your First Java Program

• Create a new Java project (e.g., "HelloWorld").
• Code to print "Hello World!" using System.out.println("Hello World!");.
  • Use shortcuts for executing code (e.g., Ctrl + R in IntelliJ).

Execution Process

1. Compilation & Execution
   • Java code compiled into bytecode using JDK.
2. Java Virtual Machine (JVM)
   • Converts bytecode into native code for the host OS.

Facts About Java

• Developed by James Gosling in 1995 at Sun Microsystems.
• Four editions: Standard, Enterprise, Micro, Card.
• Java is platform-independent.
• Search for Java APIs for frequently used classes.

Course Structure

• Part 1: Fundamentals of programming with Java.
• Part 2: Object-oriented programming.
• Part 3: Core Java APIs.
• Part 4: Advanced Java features (streams, threads, database programming).

Variables and Constants

• Use variables to store data temporarily.
• Constants (final keyword) do not change once assigned.
• Naming conventions: Use descriptive names, camelCase for variables.

Primitive and Reference Types

• Primitive Types: (byte, short, int, long, float, double, char, boolean).
• Reference Types: Store references to objects.

Expressions and Operators

• Arithmetic operators: +, -, *, /, % (modulus).
• Increment and decrement operators (++, --).
• Compound assignment operators (+=, -=).*

Control Flow Statements

1. If statements for conditionals.
2. Switch statements for alternative branches.
3. Loops:
   • For loops.
   • While loops.
   • Do-while loops.
   • For-each loops for iterating over arrays.
4. Break and Continue statements.

Clean Code Practices

• Write understandable and maintainable code.
• Use meaningful names for methods, variables, and classes.
• Break down long methods into smaller methods.

Error Handling and Input Validation

• Use loops to validate user input while handling errors gracefully.
• Use Scanner to read user inputs and validate against expected values.

Practice Project: Mortgage Calculator

• Calculation involves principal, interest rates, and time period.
• Validate inputs and enhance the calculator using methods for clarity.

Final Tips

• Always aim for clean, readable code.
• Familiarize yourself with the Java ecosystem and community practices.