Basic Java Programs Examples With Output

Java is one of the most popular programming languages, known for its versatility, portability, and wide range of applications. Whether you’re a beginner or an experienced developer, practicing basic Java programs is essential to understanding the language’s core concepts. In this blog, we’ll explore 10 basic Java programs with examples and their corresponding outputs. These programs cover fundamental topics like variables, loops, conditionals, arrays, and more. Let’s dive in!

1. Hello World Program

The “Hello World” program is the simplest Java program and is often the first step for beginners.

Code:

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

Output:

Hello, World!

Explanation:

• public class HelloWorld: Defines a class named HelloWorld.
• public static void main(String[] args): The main method, which is the entry point of the program.
• System.out.println("Hello, World!");: Prints the text “Hello, World!” to the console.

2. Addition of Two Numbers

This program demonstrates how to perform basic arithmetic operations in Java.

Code:

public class AddNumbers {
    public static void main(String[] args) {
        int num1 = 5;
        int num2 = 10;
        int sum = num1 + num2;
        System.out.println("Sum: " + sum);
    }
}

Output:

Sum: 15

Explanation:

• int num1 = 5; and int num2 = 10;: Declare and initialize two integer variables.
• int sum = num1 + num2;: Adds the two numbers and stores the result in sum.
• System.out.println("Sum: " + sum);: Prints the result.

3. Check if a Number is Even or Odd

This program checks whether a given number is even or odd.

Code:

public class EvenOdd {
    public static void main(String[] args) {
        int num = 7;
        if (num % 2 == 0) {
            System.out.println(num + " is even.");
        } else {
            System.out.println(num + " is odd.");
        }
    }
}

Output:

7 is odd.

Explanation:

• if (num % 2 == 0): Checks if the number is divisible by 2.
• If true, the number is even; otherwise, it’s odd.

4. Find the Largest of Two Numbers

This program compares two numbers and prints the larger one.

Code:

public class LargestNumber {
    public static void main(String[] args) {
        int num1 = 12;
        int num2 = 15;
        if (num1 > num2) {
            System.out.println(num1 + " is larger.");
        } else {
            System.out.println(num2 + " is larger.");
        }
    }
}

Output:

15 is larger.

Explanation:

• Compares num1 and num2 using an if-else statement.
• Prints the larger number.

5. Factorial of a Number

This program calculates the factorial of a number using a loop.

Code:

public class Factorial {
    public static void main(String[] args) {
        int num = 5;
        int factorial = 1;
        for (int i = 1; i <= num; i++) {
            factorial *= i;
        }
        System.out.println("Factorial of " + num + " is: " + factorial);
    }
}

Output:

Factorial of 5 is: 120

Explanation:

• Uses a for loop to multiply numbers from 1 to num.
• Stores the result in factorial.

6. Fibonacci Series

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

Code:

public class Fibonacci {
    public static void main(String[] args) {
        int n = 10, firstTerm = 0, secondTerm = 1;
        System.out.println("Fibonacci Series:");
        for (int i = 1; i <= n; i++) {
            System.out.print(firstTerm + " ");
            int nextTerm = firstTerm + secondTerm;
            firstTerm = secondTerm;
            secondTerm = nextTerm;
        }
    }
}

Output:

Fibonacci Series:
0 1 1 2 3 5 8 13 21 34

Explanation:

• Uses a loop to generate the Fibonacci sequence.
• Each term is the sum of the two preceding ones.

7. Reverse a Number

This program reverses a given number.

Code:

public class ReverseNumber {
    public static void main(String[] args) {
        int num = 1234, reversed = 0;
        while (num != 0) {
            int digit = num % 10;
            reversed = reversed * 10 + digit;
            num /= 10;
        }
        System.out.println("Reversed Number: " + reversed);
    }
}

Output:

Reversed Number: 4321

Explanation:

• Uses a while loop to extract digits and reverse the number.

8. Check if a Number is Prime

This program checks whether a number is prime.

Code:

public class PrimeNumber {
    public static void main(String[] args) {
        int num = 29;
        boolean isPrime = true;
        for (int i = 2; i <= num / 2; i++) {
            if (num % i == 0) {
                isPrime = false;
                break;
            }
        }
        if (isPrime) {
            System.out.println(num + " is a prime number.");
        } else {
            System.out.println(num + " is not a prime number.");
        }
    }
}

Output:

29 is a prime number.

Explanation:

• Checks divisibility of num by numbers from 2 to num/2.
• If divisible, num is not prime.

9. Sum of Array Elements

This program calculates the sum of elements in an array.

Code:

public class SumArray {
    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5};
        int sum = 0;
        for (int num : arr) {
            sum += num;
        }
        System.out.println("Sum of array elements: " + sum);
    }
}

Output:

Sum of array elements: 15

Explanation:

• Uses a for-each loop to iterate through the array and calculate the sum.

10. Palindrome Check

This program checks if a string is a palindrome.

Code:

public class Palindrome {
    public static void main(String[] args) {
        String str = "madam";
        String reversed = new StringBuilder(str).reverse().toString();
        if (str.equals(reversed)) {
            System.out.println(str + " is a palindrome.");
        } else {
            System.out.println(str + " is not a palindrome.");
        }
    }
}

Output:

madam is a palindrome.

Explanation:

• Reverses the string and compares it with the original.

Conclusion

These basic Java programs are a great starting point for beginners to understand the language’s syntax and logic. By practicing these examples, you’ll build a strong foundation in Java programming. As you progress, you can explore more advanced topics like object-oriented programming, data structures, and algorithms.

Found this blog helpful? Share it with your friends and leave a comment below with your favorite Java program!