Walmart Software Engineer III Interview Questions and Answers

Q1. Explain useState for managing state, useEffect for handling side effects, useMemo for performance optimization, and useCallback for memoizing functions. Understand how these hooks enhance functional compon...read more
Ans. 
Explanation of useState, useEffect, useMemo, and useCallback hooks in React functional components.
• useState is used to manage state in functional components

• useEffect is used for handling side effects like data fetching, subscriptions, etc.

• useMemo is used for performance optimization by memoizing expensive calculations

• useCallback is used for memoizing functions to prevent unnecessary re-renders

• These hooks enhance functio...read more
Answered by AI
Add your answer
Q2. Describe lifecycle methods in class components and their functional equivalents with hooks. Know how to handle component mounting, updating, and unmounting.
Ans. 
Lifecycle methods in class components and their hooks equivalents manage component behavior during mounting, updating, and unmounting.
• componentDidMount: Runs after the component is mounted. Use useEffect(() => { /* code */ }, []); for hooks.

• componentDidUpdate: Invoked after updates. Use useEffect(() => { /* code */ }, [dependencies]); for hooks.

• componentWillUnmount: Cleanup before unmounting. Use return function ...read more
Answered by AI
Add your answer
Q3. Understand setting up a Redux store, connecting components, and managing actions and reducers. Be familiar with middleware like Redux Thunk or Redux Saga for handling asynchronous actions.
Ans. 
Setting up Redux store, connecting components, managing actions and reducers, and using middleware like Redux Thunk or Redux Saga for handling asynchronous actions.
• Setting up a Redux store involves creating a store with createStore() function from Redux, combining reducers with combineReducers(), and applying middleware like Redux Thunk or Redux Saga.

• Connecting components to the Redux store can be done using the connec...read more
Answered by AI
Add your answer
Q4. How to add and manipulate elements in arrays using JavaScript (e.g., inserting "watermelon" in the middle)?
Ans. 
To add and manipulate elements in arrays using JavaScript, you can use array methods like splice() and slice().
• Use the splice() method to insert elements into an array at a specific index. For example, arr.splice(index, 0, 'watermelon') will insert 'watermelon' at the specified index without removing any elements.

• To manipulate elements in an array, you can use methods like splice() to remove elements or slice() to extr...read more
Answered by AI
Add your answer
Q5. Use and purpose of Math.floor() in JavaScript.
Ans. 
Math.floor() is a method in JavaScript that rounds a number down to the nearest integer.
• Math.floor() returns the largest integer less than or equal to a given number.

• It is commonly used to convert a floating-point number to an integer.

• Example: Math.floor(3.9) returns 3.
Answered by AI
Add your answer
Q6. Mocking components in Jest, including handling props and named exports
Ans. 
Mocking components in Jest for testing with props and named exports
• Use jest.mock() to mock components and their exports

• For handling props, use jest.fn() to create mock functions and pass them as props to the component being tested

• For named exports, use jest.mock() with a second argument to specify the module's exports
Answered by AI
Add your answer

Q1. Print even and odd numbers using two threads simultaneously so it should print in sequence
Ans. 
Use two threads to print even and odd numbers in sequence
• Create two threads, one for printing even numbers and one for printing odd numbers

• Use synchronization mechanisms like mutex or semaphore to ensure numbers are printed in sequence

• Start both threads simultaneously and let them print numbers alternately
Answered by AI
Add your answer

Q1. Core java questions and project discussion
Add your answer

Q1. Cycle in linked list and behavioral
Ans. 
Detecting cycle in a linked list and discussing behavioral aspects
• Explain how to use Floyd's Tortoise and Hare algorithm to detect a cycle in a linked list

• Discuss the importance of understanding memory management in linked lists to prevent cycles

• Explain the impact of cycles in linked lists on time complexity and space complexity of algorithms
Answered by AI
Add your answer

Q1. Few DSA related questions
Add your answer
Q2. Mid level SQL questions
Add your answer

SQL, python, PySpark basic to mid level questions.

Q1. Basic project related questions
Add your answer
Q2. Some prior experience questions
Add your answer

Q1. DSA: Trapping Rain Water Leeetcode
Ans. 
Calculate the amount of water that can be trapped between bars after rainfall using heights of bars.
• Use two pointers to traverse the array from both ends towards the center.

• Maintain two variables to track the maximum height from the left and right.

• At each step, calculate trapped water based on the minimum of the two maximum heights.

• Example: For heights [0,1,0,2,1,0,1,3,2,1,2,1], the trapped water is 6.
Answered by AI
Add your answer
Q2. Dynamic Programming Question
Add your answer

Q1. Java Basics - Stack vs heap memory, Advanced java concepts, Design patterns
Add your answer
Q2. Spring Boot, JPA, Bean lifecycle, Stereotypes, Multithreading, String pool
Add your answer

Q1. Resume projects, Caching
Add your answer
Q2. Kafka
Add your answer