Java Course Overview

Introduction to Java

• Java is a widely-used programming language utilized by major companies like Google, Facebook, Twitter, Spotify, and AWS.
• It's a mature language with extensive libraries, packages, and a strong community.
• Learning Java opens doors to learning other programming languages.
• Java is taught in universities and boot camps.

Characteristics of Java

• Object-Oriented Programming (OOP): Everything in Java can be modeled as an object (e.g., strings, dates).
• History: Created by James Gosling in 1995.
• Stability: Java is established and ideal for building large-scale enterprise applications.
• Popularity: "Java runs on three billion devices"; it continues to be a preferred choice for backend applications.

Comparison with Other Languages

• Java is similar to C++ but manages memory automatically, making it more beginner-friendly.
• Learning Java provides foundational knowledge applicable to other languages (Python, JavaScript, Golang).

Applications Built with Java

• Java can be used to build:
  • Mobile apps for Android (though Kotlin is becoming popular).
  • Desktop applications (Java Swing, Java FX).
  • Enterprise applications (e.g., banking systems).
  • Cloud-based applications (AWS, Azure, Google Cloud).
  • Web applications (full stack).
  • Games (initial versions of Minecraft).

Development Environment

• IDEs for Java:
  • IntelliJ IDEA: Preferred IDE, offers a Community Edition (free) and Ultimate Edition.
  • Eclipse: Older, previously popular IDE for Java.
  • Visual Studio Code: A text editor with plugins available for Java.

Setting Up IntelliJ

• Download and install IntelliJ IDEA Community Edition.
• Use the JetBrains Toolbox for managing IDE installations.
• Create and configure a new Java project in IntelliJ.

Writing Your First Java Program

• Java code structure includes classes, methods, and the main method.
• Example of a basic program:

  public class Main {
      public static void main(String[] args) {
          System.out.println("Hello Java!");
      }
  }
  

Java Syntax and Structure

• Package Declaration: Used for organizing classes into namespaces.
• Classes: Fundamental building blocks in OOP, containing properties (attributes) and methods (functions).
• Methods: Blocks of code designed to perform specific tasks, reusable throughout the program.

Data Types in Java

• Primitive Data Types: int, double, boolean, char, etc.
• Reference Types: Objects, Strings, and Arrays.
  • Strings are special reference types for handling sequences of characters.

Arrays

• Arrays hold multiple values of the same type. Size is fixed upon declaration.

  int[] numbers = new int[3]; // Declares an array with 3 elements
  

• To access or modify elements, use indices (0-based).

Conditional Statements

• if-else Statements: Control flow structure to execute code blocks based on conditions.

  if (condition) {
      // code to execute if condition is true
  } else {
      // code to execute if condition is false
  }
  

Classes and Objects

• Classes serve as blueprints for creating objects.
  • Example class:

  public class Cat {
      String name;
      void meow() {
          System.out.println(name + " says meow!");
      }
  }
  

• Create objects from classes:

  Cat myCat = new Cat();
  myCat.name = "Whiskers";
  myCat.meow();
  

Conclusion

• Java is a powerful tool for backend development, enterprise applications, and more.
• Understanding the basics of Java will provide a strong foundation for further learning in programming.