Java Coding Interview Questions

title: Java Coding Interview Questions description: Common coding problems asked in Java interviews

1. String ko reverse karo

java exampleWoHoTech

String reverse(String s) {
    return new StringBuilder(s).reverse().toString();
}

2. Palindrome check karo

java exampleWoHoTech

boolean isPalindrome(String s) {
    String rev = new StringBuilder(s).reverse().toString();
    return s.equals(rev);
}

3. Fibonacci series (n terms)

void fibonacci(int n) { int a = 0, b = 1; for (int i = 0; i < n; i++) { System.out.print(a + " "); int temp = a + b; a = b; b = temp; } }

4. Array mein duplicate find karo

java exampleWoHoTech

void findDuplicates(int[] arr) {
    Set<Integer> seen = new HashSet<>();
    for (int num : arr) {
        if (!seen.add(num)) {
            System.out.println("Duplicate: " + num);
        }
    }
}

5. Two Sum problem

int[] twoSum(int[] nums, int target) { Map<Integer, Integer> map = new HashMap<>(); for (int i = 0; i < nums.length; i++) { int complement = target - nums[i]; if (map.containsKey(complement)) return new int[]{map.get(complement), i}; map.put(nums[i], i); } return new int[]{}; }

6. String mein vowels count karo

int countVowels(String s) { int count = 0; for (char c : s.toLowerCase().toCharArray()) if ("aeiou".indexOf(c) != -1) count++; return count; }

7. Factorial (recursive)

java exampleWoHoTech

long factorial(int n) {
    if (n <= 1) return 1;
    return n * factorial(n - 1);
}

8. Array ko sort karo (bubble sort)

void bubbleSort(int[] arr) { int n = arr.length; for (int i = 0; i < n - 1; i++) for (int j = 0; j < n - i - 1; j++) if (arr[j] > arr[j + 1]) { int temp = arr[j]; arr[j] = arr[j + 1]; arr[j + 1] = temp; } }

9. Second largest element dhundho

java exampleWoHoTech

int secondLargest(int[] arr) {
    int first = Integer.MIN_VALUE, second = Integer.MIN_VALUE;
    for (int n : arr) {
        if (n > first) { second = first; first = n; }
        else if (n > second && n != first) second = n;
    }
    return second;
}

10. Anagram check karo

java exampleWoHoTech

boolean isAnagram(String s1, String s2) {
    char[] a = s1.toCharArray();
    char[] b = s2.toCharArray();
    Arrays.sort(a);
    Arrays.sort(b);
    return Arrays.equals(a, b);
}

title: Java Coding Interview Questions description: Common coding problems asked in Java interviews

1. String ko reverse karo

java exampleWoHoTech

String reverse(String s) {
    return new StringBuilder(s).reverse().toString();
}

2. Palindrome check karo

java exampleWoHoTech

boolean isPalindrome(String s) {
    String rev = new StringBuilder(s).reverse().toString();
    return s.equals(rev);
}

3. Fibonacci series (n terms)

void fibonacci(int n) { int a = 0, b = 1; for (int i = 0; i < n; i++) { System.out.print(a + " "); int temp = a + b; a = b; b = temp; } }

4. Array mein duplicate find karo

java exampleWoHoTech

void findDuplicates(int[] arr) {
    Set<Integer> seen = new HashSet<>();
    for (int num : arr) {
        if (!seen.add(num)) {
            System.out.println("Duplicate: " + num);
        }
    }
}

5. Two Sum problem

6. String mein vowels count karo

int countVowels(String s) { int count = 0; for (char c : s.toLowerCase().toCharArray()) if ("aeiou".indexOf(c) != -1) count++; return count; }

7. Factorial (recursive)

java exampleWoHoTech

long factorial(int n) {
    if (n <= 1) return 1;
    return n * factorial(n - 1);
}

8. Array ko sort karo (bubble sort)

9. Second largest element dhundho

java exampleWoHoTech

int secondLargest(int[] arr) {
    int first = Integer.MIN_VALUE, second = Integer.MIN_VALUE;
    for (int n : arr) {
        if (n > first) { second = first; first = n; }
        else if (n > second && n != first) second = n;
    }
    return second;
}

10. Anagram check karo

java exampleWoHoTech

boolean isAnagram(String s1, String s2) {
    char[] a = s1.toCharArray();
    char[] b = s2.toCharArray();
    Arrays.sort(a);
    Arrays.sort(b);
    return Arrays.equals(a, b);
}

Java Coding Interview Questions

1. String ko reverse karo

2. Palindrome check karo

3. Fibonacci series (n terms)

4. Array mein duplicate find karo

5. Two Sum problem

6. String mein vowels count karo

7. Factorial (recursive)

8. Array ko sort karo (bubble sort)

9. Second largest element dhundho

10. Anagram check karo

Continue learning this concept

Java Coding Interview Questions

1. String ko reverse karo

2. Palindrome check karo

3. Fibonacci series (n terms)

4. Array mein duplicate find karo

5. Two Sum problem

6. String mein vowels count karo

7. Factorial (recursive)

8. Array ko sort karo (bubble sort)

9. Second largest element dhundho

10. Anagram check karo

Continue learning this concept