Java Programming Examples

 Here are some Java programming examples to illustrate various concepts and features of the language:

1. Hello World Program

This is a simple program that outputs the message "Hello, World!" to the console.

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

2. Calculation Program

This program prompts the user to enter two numbers and performs a calculation based on the operator entered.

java
import java.util.Scanner;

public class Calculator {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    System.out.print("Enter the first number: ");
    double num1 = scanner.nextDouble();
    System.out.print("Enter the second number: ");
    double num2 = scanner.nextDouble();
    System.out.print("Enter the operator (+, -, *, /): ");
    char operator = scanner.next().charAt(0);
    double result;

    switch (operator) {
      case '+':
        result = num1 + num2;
        break;
      case '-':
        result = num1 - num2;
        break;
      case '*':
        result = num1 * num2;
        break;
      case '/':
        result = num1 / num2;
        break;
      default:
        System.out.println("Invalid operator");
        return;
    }

    System.out.println(num1 + " " + operator + " " + num2 + " = " + result);
  }
}

3. Fibonacci Series Program

This program prints the Fibonacci series up to a specified number of terms.

java
import java.util.Scanner;

public class Fibonacci {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    System.out.print("Enter the number of terms: ");
    int n = scanner.nextInt();
    int a = 0, b = 1, c;

    System.out.print("Fibonacci series: ");
    for (int i = 1; i <= n; i++) {
      System.out.print(a + " ");
      c = a + b;
      a = b;
      b = c;
    }
  }
}

4. Factorial Program

This program calculates the factorial of a given number.

java
import java.util.Scanner;

public class Factorial {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    System.out.print("Enter a number: ");
    int n = scanner.nextInt();
    int fact = 1;

    for (int i = 1; i <= n; i++) {
      fact *= i;
    }

    System.out.println("Factorial of " + n + " is " + fact);
  }
}

5. File Handling Program

This program reads a file and prints its contents to the console.

java
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class FileHandler {
  public static void main(String[] args) {
    try {
      BufferedReader reader = new BufferedReader(new FileReader("file.txt"));
      String line = reader.readLine();
      while (line != null) {
        System.out.println(line);
        line = reader.readLine();
      }
      reader.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

These are just a few examples of what can be accomplished with Java. By understanding the syntax and features of the language, you can build a wide variety of programs for different purposes.