Java Course Lecture Notes

Introduction

• Instructor: Mosh
• Course Overview: Learn Java programming from basics to advanced features.
• Designed for beginners, no prior experience required.
• Course includes tips and shortcuts based on years of professional experience.

Course Structure

• Installation: Set up tools for Java development.
• Basics of Java: Understanding how Java code executes and building simple algorithms.
• Writing Good Code: Techniques for writing clean and maintainable code.
• Advanced Features: Introduction to advanced Java concepts.

Setting Up Development Environment

1. Installing JDK

• Search for JDK download and install the Java Development Kit (JDK).
• Accept the license agreement and download the appropriate version for your OS (e.g., dmg for Mac).

2. Installing IntelliJ IDEA

• Download the Community Edition of IntelliJ IDEA, which is free.
• Install IntelliJ IDEA and set it up as the code editor for this course.

Anatomy of a Java Program

1. Structure of a Java Program

• Functions: Blocks of code that perform tasks. Example functions: sending emails, validating user inputs.
• Main Function: Every Java program must have a main function as the entry point.
• Classes: Containers for functions (methods). All Java functions must belong to a class.

2. Access Modifiers

• Define visibility of classes and methods (e.g., public, private).

3. Naming Conventions

• Classes: Use Pascal case (e.g., MainClass).
• Methods: Use camel case (e.g., sendEmail).

Creating Your First Java Project

• Open IntelliJ, create a new Java project, and set up the project SDK.
• Create a command-line application.
• Define a base package for organizing your code.

Writing Your First Java Program

• Use System.out.println to print messages to the terminal.
• Java uses the dot operator to access methods and members of classes.
• Understand the need for comments in code for better comprehension.

Java Code Execution

• Compilation: Java code gets compiled into bytecode, which is platform-independent.
• Execution: The Java Virtual Machine (JVM) converts bytecode to native code for execution.

Interesting Facts About Java

• Developed by James Gosling at Sun Microsystems in 1995.
• Java has several editions: Standard Edition, Enterprise Edition, Micro Edition, and Java Card.
• Java is widely used across various platforms and applications.
• Average salary of a Java developer in the US is over $100,000.

Course Overview

• Section 1: Fundamentals of programming with Java.
• Section 2: Type system, working with various types like strings and arrays.
• Section 3: Control flow statements for building algorithms.
• Section 4: Clean coding practices for writing maintainable code.
• Section 5: Error handling and packaging applications for deployment.

Variables and Constants in Java

• Variables store data temporarily in memory.
• Types: primitive (e.g., int, float, bool) and non-primitive/reference types (e.g., strings, arrays).

Declaring and Using Variables

• Use meaningful names for variables.
• Use camel case for variable names.
• Understand variable scope and lifetime.

Data Types in Java

• Primitive Types:

  • byte, short, int, long: for whole numbers.
  • float, double: for decimal numbers.
  • char: for single characters.
  • boolean: for true/false values.

• Reference Types: Hold references to complex objects, like instances of classes.

Implicit and Explicit Casting

• Implicit casting happens automatically when converting smaller to larger types.
• Explicit casting is done using parentheses to specify the type.

Control Flow Statements

1. Conditional Statements

• If-Else Statements: Used for decision-making based on conditions.
• Switch Statements: Used as an alternative to if-else for multiple conditions.

2. Loops

• For Loop: Used when the number of iterations is known.
• While Loop: Used when the number of iterations is not known beforehand.
• Do-While Loop: Ensures the loop body executes at least once.
• For Each Loop: Simplifies iteration over collections or arrays.

3. Break and Continue Statements

• Break: Exits the loop.
• Continue: Skips the current iteration and continues with the next.

Project: Mortgage Calculator

• Implement user input validation.
• Handle invalid inputs using loops and conditionals.
• Format output using the NumberFormat class for currency.

Conclusion

• Recap of variables, constants, data types, control flow, loops, and project development.
• Importance of clean coding for maintainable software.
• Encouragement to enroll in a complete Java series for deeper learning.