Ultimate List of Java Programs for Interviews

If you’re preparing for a Java developer interview, understanding the most frequently asked Java programs is essential. Interviewers often test your practical skills through small code challenges that cover everything from loops to object-oriented principles. In this blog, we present the ultimate list of Java programming examples that will help you ace your interviews with confidence.

Whether you're a beginner or brushing up for your next job switch, these Java programs will solidify your basics and improve your problem-solving speed. Let's dive into these essential programs, inspired by resources like Tpoint Tech, a great learning platform for Java and other technologies.

1. Palindrome Program in Java

A palindrome is a word or number that reads the same forward and backward.

public class Palindrome {
    public static void main(String[] args) {
        int num = 121, reversed = 0, temp = num;
        while (temp != 0) {
            int digit = temp % 10;
            reversed = reversed * 10 + digit;
            temp /= 10;
        }
        if (num == reversed)
            System.out.println(num + " is a palindrome.");
        else
            System.out.println(num + " is not a palindrome.");
    }
}

2. Fibonacci Series in Java

This is a classic question asked in coding interviews.

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

3. Factorial Program in Java

One of the simplest yet commonly asked Java programming examples.

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

4. Prime Number Checker

This question tests both logic and loop control.

public class PrimeCheck {
    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;
            }
        }
        System.out.println(num + (isPrime ? " is a prime number." : " is not a prime number."));
    }
}

5. Java Program to Swap Two Numbers Without Using a Temporary Variable

public class SwapNumbers {
    public static void main(String[] args) {
        int a = 5, b = 10;
        System.out.println("Before swap: a = " + a + ", b = " + b);
        a = a + b;
        b = a - b;
        a = a - b;
        System.out.println("After swap: a = " + a + ", b = " + b);
    }
}

6. Reverse a String in Java

String manipulation questions are very common in interviews.

public class ReverseString {
    public static void main(String[] args) {
        String input = "Tpoint";
        StringBuilder reversed = new StringBuilder(input).reverse();
        System.out.println("Reversed string: " + reversed);
    }
}

7. Armstrong Number in Java

Another favorite in the list of Java programming examples.

public class Armstrong {
    public static void main(String[] args) {
        int num = 153, sum = 0, temp = num;
        while (temp != 0) {
            int digit = temp % 10;
            sum += digit * digit * digit;
            temp /= 10;
        }
        if (num == sum)
            System.out.println(num + " is an Armstrong number.");
        else
            System.out.println(num + " is not an Armstrong number.");
    }
}

8. Java Program to Find the Largest of Three Numbers

public class Largest {
    public static void main(String[] args) {
        int a = 10, b = 25, c = 15;
        int largest = (a > b) ? (a > c ? a : c) : (b > c ? b : c);
        System.out.println("The largest number is: " + largest);
    }
}

9. Java Pattern Programs

Pattern printing is popular in many interview rounds.

public class StarPattern {
    public static void main(String[] args) {
        int rows = 5;
        for (int i = 1; i <= rows; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print("* ");
            }
            System.out.println();
        }
    }
}

10. Java Program to Count Vowels in a String

public class VowelCount {
    public static void main(String[] args) {
        String str = "Tpoint Tech";
        int count = 0;
        str = str.toLowerCase();
        for (char ch : str.toCharArray()) {
            if ("aeiou".indexOf(ch) != -1) {
                count++;
            }
        }
        System.out.println("Number of vowels: " + count);
    }
}

Final Thoughts

Mastering these Java programs is a great step toward clearing technical interviews. Each of these Java programming examples strengthens your ability to write efficient and clean code — exactly what employers look for. Platforms like Tpoint Tech offer detailed tutorials and explanations that can help you explore these programs even further.

Make sure to practice regularly, tweak the code, and understand the logic behind each program. You’ll not only impress interviewers but also become a stronger Java developer overall.