80+ Senior Sdet Engineer Interview Questions and Answers

Implement a data structure like a hash table or a cache to optimize memory search.

• Use a hash table to store the data with keys as memory locations

• Implement a cache to store frequently accessed data for faster retrieval

• Consider using indexing or sorting techniques to optimize search operations

Code to split a string into one letter per line in an array of strings.

• Use the split() method to split the string into an array of characters.

• Iterate through the array and add each character to a new array as a separate string.

Xpath of an element from amazon.in page

• Start with the root element using '/'

• Use '//' to select any element in the document

• Use '@' to select attributes

• Use '[]' for conditions

• Example: //div[@id='nav-logo']

Selenium is a popular open-source tool used for automating web browsers in software testing.

• Selenium is used to automate web browsers for testing purposes.

• It supports multiple programming languages like Java, Python, C#, etc.

• Selenium can interact with web elements, simulate user actions, and validate expected outcomes.

• It can be integrated with testing frameworks like TestNG or JUnit for test execution and reporting.

• Selenium WebDriver is the most commonly used component for wr...read more

Reverse a string input without using any inbuilt method in Java

• Create a char array from the input string

• Use two pointers to swap characters from start and end of the array

• Continue swapping until the pointers meet in the middle

Automate a website using code

• Use Selenium WebDriver to automate interactions with the website

• Identify elements on the website using CSS selectors or XPaths

• Perform actions like clicking buttons, filling forms, and verifying text

• Handle waits for elements to load properly

• Use programming languages like Java, Python, or JavaScript for scripting

Create a class, test methods, create object, and call them in code.

• Create a class with properties and methods

• Write test methods to test the functionality of the class

• Instantiate an object of the class and call its methods

Yes, we can run tests locally without environment by using mock objects or stubs.

• Use mock objects or stubs to simulate the behavior of external dependencies

• Mocking frameworks like Mockito or Sinon can be used to create mock objects

• Avoid relying on external services or databases for local testing

Reverses strings in an array and adds stars between characters

• Iterate through each string in the array

• Reverse each string using built-in functions or manual reversal

• Add stars between characters in the reversed string

• Return the modified array of strings

Method overloading allows multiple methods with the same name but different parameters in a class.

• Method overloading in our framework allows us to create multiple methods with the same name but different parameters.

• For example, we can have a method 'calculate' that can take different types of parameters like int, double, or string.

• This helps in improving code readability and reusability.

• Method overloading is resolved at compile time based on the number and type of arguments p...read more

Build testing is testing the software build to ensure it meets requirements. Shift left testing is moving testing earlier in the development process.

• Build testing involves testing the software build to ensure it meets functional and non-functional requirements

• Shift left testing is the practice of moving testing activities earlier in the software development process to catch defects sooner

• By shifting testing left, defects are identified and fixed earlier, reducing the cost and...read more

In Java, exceptions are handled using try-catch blocks, allowing graceful error management and maintaining program flow.

• Use try-catch blocks to catch exceptions: try { // code that may throw an exception } catch (ExceptionType e) { // handle exception }

• Use finally block for cleanup: try { // code } catch (Exception e) { // handle exception } finally { // cleanup code }

• Throw exceptions using 'throw' keyword: throw new ExceptionType("Error message");

• Create custom exceptions by ...read more

Cassandra is a distributed NoSQL database management system designed for handling large amounts of data across multiple servers.

• Cassandra is used for storing and managing large amounts of structured data across multiple commodity servers.

• It provides high availability and fault tolerance with no single point of failure.

• Cassandra is commonly used for real-time analytics, IoT data, messaging platforms, and more.

• It uses a decentralized architecture with a masterless design, allow...read more

Static variables and methods can be accessed using the class name directly.

• Use the class name followed by a dot operator to access static variables and methods.

• No instance of the class is required to access static members.

• Example: ClassName.staticVariableName or ClassName.staticMethodName()

Java program to print words by ascending count value

• Create a HashMap to store word frequencies

• Iterate through the array of strings and update the frequencies in the HashMap

• Use a TreeMap to sort the HashMap by values in ascending order

• Print the words in ascending count value order

String buffer is synchronized and thread-safe, while string builder is not synchronized and faster.

• String buffer is synchronized, making it thread-safe for use in multi-threaded environments.

• String builder is not synchronized, making it faster but not thread-safe.

• String builder is preferred for single-threaded operations due to its faster performance.

• String buffer is used when thread safety is required, even though it may be slower in some cases.

To log latency for an API, you can use logging frameworks like Log4j or SLF4J to record timestamps before and after the API call.

• Use a logging framework like Log4j or SLF4J to record timestamps before and after the API call

• Calculate the latency by subtracting the timestamps

• Include the latency information in the log message for monitoring and analysis

To scroll a web element, use actions class to perform scroll actions

• Create an instance of Actions class

• Use moveToElement() method to move to the desired element

• Perform scroll actions using sendKeys(Keys.ARROW_DOWN) or sendKeys(Keys.PAGE_DOWN)

• Example: Actions actions = new Actions(driver); actions.moveToElement(element).sendKeys(Keys.ARROW_DOWN).perform();

Implicit wait is set globally for all elements, while explicit wait is applied only to specific elements.

• Implicit wait is set using driver.manage().timeouts().implicitlyWait() method

• Explicit wait is set using WebDriverWait class with ExpectedConditions

• Implicit wait is applied globally to all elements, while explicit wait is applied only to specific elements

• Implicit wait is used to wait for elements to load before performing actions, while explicit wait is used to wait for spe...read more

Java program to display unique characters in an array of strings

• Iterate through each string in the array

• Use a HashSet to keep track of unique characters

• For each character in the string, check if it is already in the HashSet and add it if not

Interfaces define contracts for classes, while abstraction hides implementation details, focusing on essential features.

• An interface can contain method signatures but no implementation, e.g., 'public interface Animal { void makeSound(); }'

• Abstraction can be achieved using abstract classes, which can have both abstract methods and concrete methods, e.g., 'abstract class Shape { abstract void draw(); }'

• A class can implement multiple interfaces, promoting multiple inheritance, w...read more

BDD framework in test automation focuses on behavior-driven development principles to create automated tests.

• BDD framework uses natural language to define test scenarios

• Tests are written in a human-readable format using Given-When-Then syntax

• Tools like Cucumber and SpecFlow are commonly used for BDD test automation

POM stands for Page Object Model, a design pattern used in test automation to create reusable and maintainable code by separating test scripts from web elements.

• POM helps in creating a clear separation between test code and page-specific code

• Each web page is represented as a separate class in POM

• Page Objects contain the locators and methods to interact with the elements on that page

• POM promotes code reusability and maintainability in test automation

The best time to buy or sell stock depends on various factors such as market conditions, company performance, and personal financial goals.

• Consider buying stocks when the market is down and selling when it is up to maximize profits.

• Research the company's financial health, growth potential, and industry trends before making a decision.

• Set clear investment goals and risk tolerance to determine the best time to buy or sell stocks.

• Diversify your portfolio to reduce risk and prote...read more

A mean heap is a data structure that minimizes the cost of accessing the smallest element.

• Mean heap is a type of binary heap where the value of each node is less than or equal to the values of its children.

• It is useful for finding the minimum element quickly, as the root node always contains the smallest value.

• Insertion and deletion operations in a mean heap have a time complexity of O(log n).

A binary search tree (BST) is a data structure that organizes elements in a hierarchical manner, allowing for efficient searching, insertion, and deletion.

• BST is a type of binary tree where each node has at most two children.

• The left child of a node is always smaller than the node, and the right child is always greater.

• BST allows for efficient searching with a time complexity of O(log n) on average.

• Common operations on BST include insertion, deletion, and searching for a spec...read more

Private matter

• Personal

• Intimate

CORS issues occur when a web application tries to make a request to a different domain than the one it originated from.

• Enable CORS on the server by adding appropriate headers like Access-Control-Allow-Origin

• Use a proxy server to make requests on behalf of the client

• Ensure that the client-side code is making requests correctly with the appropriate headers

• Consider using JSONP as an alternative to CORS in some cases

To create a CI/CD job, you need to define the steps for building, testing, and deploying code automatically.

• Define the source code repository to pull code from

• Set up build steps to compile code and run tests

• Configure deployment steps to deploy code to target environments

• Integrate with version control system for triggering builds on code changes

• Use CI/CD tools like Jenkins, GitLab CI, or CircleCI

A library for API testing that provides a set of functions and utilities to simplify the testing process.

• The library should have functions to send HTTP requests and validate responses.

• It should support different authentication methods like OAuth, JWT, etc.

• The library should handle common API testing scenarios like testing CRUD operations, handling different HTTP methods, etc.

• It should provide utilities for data-driven testing, allowing testers to easily parameterize and itera...read more

An automation framework is a set of guidelines, rules, and tools that help in creating and executing automated tests.

• Provides structure and organization for automated testing

• Defines how tests are written, executed, and reported

• Includes libraries, utilities, and templates for test automation

• Supports integration with test management tools and version control systems

• Examples: Selenium WebDriver, TestNG, JUnit, Cucumber

Virtualization is the process of creating a virtual version of a device or resource, such as a server, storage device, network or operating system.

• Virtualization allows multiple virtual instances to run on a single physical machine

• It helps in optimizing resources and increasing efficiency

• Examples include VMware, VirtualBox, and Hyper-V

An automation framework is a set of guidelines, rules, and tools that help in creating automated tests for software applications.

• Automation frameworks provide structure and organization for automated testing

• They help in reducing the effort required to maintain and update automated tests

• Frameworks can include libraries, coding standards, and best practices for test automation

• Examples of automation frameworks include Selenium, TestNG, and Robot Framework

Python code to reverse an array of strings

• Use the built-in function 'reverse()' to reverse the array of strings

• Alternatively, you can use slicing to reverse each individual string in the array

Java program to split a string into an array of strings

• Use the split() method of the String class to split the string based on a delimiter

• Store the result in an array of strings

• Example: String str = 'Hello,World'; String[] parts = str.split(',');

Data structure is a way of organizing and storing data in a computer so that it can be accessed and manipulated efficiently.

• Data structures define the way data is organized and stored in memory.

• Examples include arrays, linked lists, stacks, queues, trees, and graphs.

• Choosing the right data structure is crucial for efficient data manipulation and retrieval.

React is a JavaScript library for building user interfaces.

• React allows developers to create reusable UI components.

• It uses a virtual DOM for efficient updates.

• React is maintained by Facebook and a community of developers.

• JSX is a syntax extension used in React to write HTML-like code within JavaScript.

Kafka is a distributed streaming platform used for building real-time data pipelines and streaming applications.

• Kafka is designed to handle high-throughput, fault-tolerant, and scalable real-time data streams.

• It allows for the publishing and subscribing to streams of records, similar to a message queue.

• Kafka is often used for log aggregation, stream processing, event sourcing, and real-time analytics.

• It provides features such as fault tolerance, replication, and partitioning ...read more

Handle bugs by identifying, prioritizing, fixing, and testing them to ensure quality software.

• Identify bugs by reproducing them and analyzing logs

• Prioritize bugs based on impact and severity

• Fix bugs by writing code changes and performing code reviews

• Test fixes to ensure they resolve the issue without introducing new bugs

As a Senior SDET Engineer, my role in the company is to design, develop, and maintain automated testing frameworks to ensure the quality of software products.

• Designing and implementing automated testing frameworks

• Developing test scripts and scenarios

• Collaborating with developers and QA teams to identify and fix software defects

• Participating in code reviews and providing feedback on testability

• Analyzing test results and providing recommendations for improvements

String reverse is the process of reversing the order of characters in a string.

• Create a new string and iterate through the original string in reverse order, appending each character to the new string.

• Use built-in functions like reverse() in some programming languages to reverse the string directly.

• Implement a custom algorithm to swap characters from the beginning and end of the string until reaching the middle.

Count the occurrences of '-/1' in a given array of strings.

• Iterate through the array and count the number of times '-/1' appears in each string.

• Use a loop to go through each element of the array and check for the substring '-/1'.

• Keep a counter to track the total occurrences of '-/1' in the array.

Cucumber is a testing framework that supports Behavior Driven Development (BDD) using plain language for writing test cases.

• Cucumber allows writing test cases in Gherkin language, which is human-readable.

• It promotes collaboration between developers, testers, and non-technical stakeholders.

• Example of a Gherkin scenario: 'Given the user is on the login page, When they enter valid credentials, Then they should be redirected to the dashboard.'

• Cucumber integrates with various prog...read more

Agile ceremonies are regular meetings or events in Agile methodology to facilitate communication, collaboration, and decision-making within the team.

• Sprint Planning: Setting goals and planning work for the upcoming sprint.

• Daily Stand-up: Short daily meeting to discuss progress, challenges, and plans for the day.

• Sprint Review: Demo of completed work to stakeholders for feedback.

• Sprint Retrospective: Reflecting on the sprint and identifying areas for improvement.

• Backlog Groomin...read more

A palindrome is a word, phrase, number, or other sequence of characters that reads the same forward and backward.

• Create a string variable with a word or phrase that is the same forward and backward.

• Use a loop to compare the characters from the beginning and end of the string to check if it is a palindrome.

• Ignore spaces and punctuation when checking for palindromes.

• Example: 'racecar' is a palindrome.