Basic Java Programming Examples and Solutions

Introduction

Java is a versatile programming language used for building various applications, from simple web pages to complex enterprise systems. Mastering its fundamentals is crucial for any aspiring programmer. This guide explores common Java programming examples and their solutions, providing insights into essential concepts and techniques.

1. Printing “Hello, World!”

Problem: Display the message “Hello, World!” on the console.

Solution:

Java

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

Explanation:

• public class HelloWorld declares a class named HelloWorld.
• public static void main(String[] args) is the main method, the program’s entry point.
• System.out.println() prints the message to the console.

2. Finding the Sum of Two Numbers

Problem: Take two numbers as input and calculate their sum.

Solution:

Java

import java.util.Scanner;

public class SumOfTwoNumbers {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter first number: ");
        int num1 = scanner.nextInt();

        System.out.print("Enter second number: ");
        int num2 = scanner.nextInt();

        int sum = num1 + num2;
        System.out.println("Sum of the numbers: " + sum);
    }
}

3. Checking for Even or Odd Numbers

Problem: Determine whether a given number is even or odd.

Solution:

Java

import java.util.Scanner;

public class EvenOddChecker {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter a number: ");
        int num = scanner.nextInt();

        if (num % 2 == 0) {
            System.out.println(num + " is even.");
        } else {
            System.out.println(num + " is odd.");
        }
    }
}

4. Finding the Largest Number among Three

Problem: Identify the largest number among three given numbers.

Solution:

Java

import java.util.Scanner;

public class LargestNumberFinder {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // ... (Prompt for and read three numbers)

        // Find the largest number using conditional statements
        // ...
    }
}

5. Swapping Two Numbers

Problem: Exchange the values of two variables without using a temporary variable.

Solution:

Java

// ... (Declare and initialize two variables)

// Swap the values using arithmetic operations
// ...

Additional Examples and Solutions

• Calculating factorials
• Finding prime numbers
• Reversing a string
• Sorting numbers or strings
• Generating patterns like pyramids or stars
• Working with arrays
• Implementing basic data structures like linked lists or stacks

Conclusion

These basic Java programming examples provide a foundation for understanding core concepts like variables, data types, operators, control flow, input/output, and more. By practicing and experimenting with these examples, you’ll gain confidence in writing Java code and prepare for more advanced programming tasks.