Welcome to the basics of Java! Java is a popular programming language known for its "write once, run anywhere" philosophy. This guide will cover the fundamental concepts of Java programming.

Getting Started

Before diving into Java, make sure you have the following:

  • Java Development Kit (JDK)
  • Integrated Development Environment (IDE) like IntelliJ IDEA or Eclipse

Hello World

The "Hello World" program is a classic way to get started with any programming language. Here's a simple Java program to display "Hello, World!" on the console:

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

Variables

In Java, variables are used to store data. Here's an example of declaring and initializing a variable:

int number = 5;

Data Types

Java has several data types, including:

  • Primitive Types: int, float, double, char, boolean
  • Reference Types: String, Array, Class, Interface

Control Structures

Control structures allow you to control the flow of your program. Here are some common ones:

  • If-Else: Conditionally execute code blocks
  • For Loop: Iterate over a sequence of values
  • While Loop: Continue executing a block of code as long as a condition is true

Functions

Functions are reusable blocks of code that perform a specific task. Here's an example of a function that adds two numbers:

public static int add(int a, int b) {
    return a + b;
}

Object-Oriented Programming (OOP)

Java is an object-oriented programming language. This means you can create objects that represent real-world entities. Here are some key concepts:

  • Classes: Blueprints for creating objects
  • Objects: Instances of classes
  • Inheritance: Creating new classes based on existing ones
  • Polymorphism: Allowing objects of different classes to be treated as instances of a common superclass

Resources

For more information on Java, check out the following resources:

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