Java Coding Series Overview

Introduction

• Series designed to teach Java coding from scratch
• Includes 15 hands-on projects
• Final project: Functioning alarm clock that plays music
• Starts from basics, no prior experience needed

Java Setup Requirements

• Java Development Kit (JDK): Contains compiler to compile source code to byte code
  • Download latest version (e.g., JDK 23 from Oracle)
• Integrated Development Environment (IDE): Recommended: IntelliJ Community Edition
  • Enables writing and managing code effectively

First Java Program

• Project Setup in IntelliJ: Create new project, select JDK version
  • Name project and avoid sample code generation for hands-on learning
• Main Method Structure: Required method for program execution
  • public static void main(String[] args)
• Basic Output: Using System.out.println() for console output
  • Print statements and escape sequences for formatting
• Comments: Utilize // for single line and /* */ for multi-line

Java Variables and Data Types

• Primitive Data Types: int, double, char, boolean
  • Integers and doubles for numbers; chars for characters; booleans for true/false
• Reference Data Types: Strings, arrays, objects
  • Strings for text, arrays for collections, objects for custom data structures
• Variable Declaration and Initialization
  • Declaration: int age;
  • Assignment: age = 21;
• Output with Variables: Concatenating variables with text
• Booleans and If Statements
  • Conditional execution based on boolean values

User Input and Scanners

• Scanner Class: For user input from console
  • Import with import java.util.Scanner;
  • Create scanner object: Scanner scanner = new Scanner(System.in);
• Reading User Input: Methods like nextLine(), nextInt(), nextDouble()
• Handling Input with Control Flow
  • Use if statements to verify input validity
• Closing Scanners: Important to close scanner after use to free resources

Java Arithmetic and Math Operations

• Operators: Addition, subtraction, multiplication, division, and modulus
• Order of Operations: PEMDAS principle for expression evaluation
• Augmented Assignments: Shortcuts like +=, -=, etc.
• Increment and Decrement: Using ++ and --

Control Flow and Loops

• If-Else Statements: Conditional logic execution
• Switch Statements: Alternative to multiple if-else, supports pattern matching
• Loops: For iterating code execution
  • While Loop: Repeats as long as condition is true
  • Do-While Loop: Executes once, then checks condition
  • For Loop: Deterministic iteration based on counter
  • Enhanced For Loop: For iterating over arrays/collections
• Break and Continue: Control loop execution

Arrays

• Definition: Collection of elements of the same type
• Declaration and Initialization
  • int[] numbers = {1, 2, 3, 4};
• Accessing Elements: Using index positions
• Array Properties: Length, iterating with loops
• Multi-Dimensional Arrays: Arrays within arrays for matrices

Collections and Advanced Data Structures

• ArrayLists: Resizable arrays with dynamic size
• HashMaps: Stores key-value pairs, efficient for lookups
• Enums: Define a fixed set of constants, useful with switches

Object-Oriented Programming (OOP)

• Classes and Objects: Blueprint and instances
• Attributes and Methods: Data and behaviors of objects
• Constructors: Initialize objects
• Inheritance: Child classes inherit parent class features
• Polymorphism: Objects processed as their superclass type
• Encapsulation: Using getters and setters to protect data
• Interfaces and Abstract Classes: Define what a class must do, not how

File Handling

• Writing to Files: Using FileWriter
• Reading from Files: Using BufferedReader and FileReader

Advanced Topics

• Multithreading and Concurrency: Running tasks simultaneously
  • Use of Runnable interface and Thread class
• Generics: Type-safe data structures
• Handling Exceptions: Using try-catch-finally for error management

Final Project: Alarm Clock

• Combines multiple Java concepts
• Features user input, time management, audio playback
• Implements threading for concurrent operations