Paytm Senior Software Developer Interview Questions and Answers

Q1. What is dependancy Injection?
Ans. 
Dependency Injection is a design pattern where the dependencies of a class are provided from the outside rather than created within the class itself.
• Allows for easier testing by providing mock dependencies

• Promotes loose coupling between classes

• Improves code reusability and maintainability

• Commonly implemented using frameworks like Spring in Java
Answered by AI
Add your answer
Q2. How We maintain security in Application?
Ans. 
Maintaining security in applications involves implementing encryption, authentication, authorization, and regular security audits.
• Implement encryption to protect data in transit and at rest

• Use strong authentication mechanisms like multi-factor authentication

• Implement proper authorization controls to restrict access to sensitive data

• Regularly conduct security audits and penetration testing to identify vulnerabilities
Answered by AI
Add your answer

Q1. Questions mostly from java 8 new features? Stream manipulation , lambda expression. functional interface, optional class
Add your answer
Q2. Java collection in depth, like Set, List, Queue, Map. Difference between them . ConcurrentHashMap is one of hot cake
Add your answer

Q1. Question based on programming like How to find 2nd highest salary of Employee by each department using stream api . How to find duplicate elements in two arrays?
Add your answer

A test that covers all fundamental topics, including networking, object-oriented programming (OOP), and data structures and algorithms (DSA).

Q1. Write code for quick sort
Add your answer
Q2. Puzzle
Add your answer

Q1. Java Fundamentals
Add your answer
Q2. System Design
Add your answer

Q1. Previous experience
Add your answer
Q2. Spring boot
Add your answer

Q1. Offer discussion
Add your answer
Q2. Onboarding process
Add your answer

Q1. Explain the react lifecycle functions and how they work
Ans. 
React lifecycle functions are methods that are automatically called at specific points in a component's life cycle.
• Mounting: constructor, render, componentDidMount

• Updating: render, componentDidUpdate

• Unmounting: componentWillUnmount
Answered by AI
Add your answer
Q2. Css box model, difference between padding and margin
Ans. 
Padding is the space inside the border of an element, while margin is the space outside the border.
• Padding is used to create space between the content and the border of an element.

• Margin is used to create space between the border of an element and other elements.

• Padding affects the size of the content area, while margin affects the positioning of the element.

• Example: padding: 10px will create 10 pixels of space inside ...read more
Answered by AI
Add your answer

Q1. What are your salary expectations in CTC and variables?
Add your answer
Q2. Will you relocate to the location required?
Add your answer

Data structures and algo. 2 ques were asked in hackerrank

Q1. Questions related to System design
Add your answer

Q1. Basic question related to Spring and Java
Add your answer

Q1. One leetcode easy-medium problem
Add your answer
Q2. Java, springboot and oops question
Add your answer

Q1. Project related questions
Add your answer
Q2. System design questions
Add your answer

You should be familiar with core java features. Collections, converting one collection Array / Vector to other. Removing duplicates. Lambda chaining / Functional programming. Basic SQL - Joins, Aggregates etc.

Q1. Explain Architecture of applications you worked on. Justify use of components. System Design questions.
Add your answer