QA / TESTING

QA Coding Questions

Practice frequently asked coding questions from real QA and test automation interviews, each with a clear, worked answer.

These questions were curated after going through 100+ sources — LinkedIn posts, Medium articles, YouTube videos, and interview experiences shared by friends — to reflect what's genuinely being asked in real QA/automation interviews.

Work through the questions in any order — each one is self-contained.

Check if a Number is Even or Odd in Java

QA Coding Questions

Check if a Number is Even or Odd in Java

Check Leap Year in Java

Check if a Vowel is Present in a String - Java

Count Vowels in a String or Array of Strings - Java

Count Non-Space Characters in a String - Java

Count Uppercase and Lowercase Letters in a String - Java

Swap Two Numbers With and Without a Temp Variable - Java

Swap Two Strings With and Without a Temp Variable - Java

Find Max and Min in an Array - Java

Sum of All Elements in an Integer Array - Java

Check if a List Contains Only Odd Numbers - Java

Reverse a String Without Using Built-in Methods - Java

Check Whether a String is a Palindrome - Java

Reverse Each Word in a Sentence While Preserving Word Order - Java

Count the Number of Words in a Sentence - Java

Check Whether All Characters in a String Are Unique - Java

Remove Spaces from a String - Java

Remove All Occurrences of a Given Character from a String - Java

Get Distinct Characters from a String - Java

Generate Fibonacci Series up to N Terms - Java

Check if a Number is Prime - Java

FizzBuzz - Print 1 to 100 with Fizz/Buzz/FizzBuzz Rules - Java

Sum of Digits of a Number - Java

Count Character Occurrences - Build a Frequency Map - Java

Find the Second Largest Number in an Array - Java

Find the Third-Largest Distinct Number in an Array - Java

Print Only Unique Values in an Array - Java

Remove Duplicates from an Integer Array - Java

Move Zeroes to the End of an Array While Maintaining Order - Java

Check if Two Arrays Contain the Same Elements - Java

Find the Missing Number from an Array Containing 1 to N - Java

Rotate an Array Left or Right by K Positions - Java

Find the Intersection of Two Arrays - Java

Two Sum - Find a Pair of Numbers Whose Sum Equals a Target - Java

Find the Maximum-Sum Contiguous Subarray (Kadane's Algorithm) - Java

Find the Maximum Average Subarray (Sliding Window) - Java

Find the Most Frequent / Majority Element in an Array - Java

Sort an Array Without Using Built-in Sorting Methods - Java

Find Factorial Using Recursion - Java

Reverse a Number / Check if a Number is a Palindrome - Java

Check Armstrong Number - Java

Find the First Repeating Character in a String - Java

Find the Duplicate Words in a Sentence - Java

Find the First Non-Repeating Element in an Integer Array - Java

Implement Binary Search and Linear Search - Java

Decimal to Binary Conversion (and Back) - Java

Find GCD/HCF of Two Numbers - Java

Find the First Non-Repeating Character in a String - Java

Count Duplicate Characters in a String - Java

Find All Duplicate Characters in a String - Java

Remove Duplicate Characters from a String - Java

Check if Two Strings Are Anagrams (Sorting or Frequency Array) - Java

Count Occurrences of Substrings/Words in Text (Log/Data-Relevant) - Java

Print a Matrix in Spiral Order - Java

Sort a HashMap by Its Values - Java