90+ 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

Volatile and static are storage classes in C/C++ that affect variable visibility and lifetime in embedded systems.

• Volatile: Tells the compiler that a variable may change unexpectedly, preventing optimization.

• Example: 'volatile int sensorValue;' - used for variables that can be changed by hardware.

• Static: Limits the visibility of a variable to the file or function it is declared in, retaining its value between function calls.

• Example: 'static int count = 0;' - count retains its...read more

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']

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

Manage pop-ups and certificates in Selenium using specific methods for handling alerts and configuring browser settings.

• Use driver.switchTo().alert() to handle JavaScript pop-ups.

• Example: Alert alert = driver.switchTo().alert(); alert.accept();

• For file upload pop-ups, use sendKeys() to set the file path directly.

• Example: driver.findElement(By.id('upload')).sendKeys('/path/to/file');

• To manage SSL certificates, configure browser options before launching.

• Example: ChromeOptions o...read more

Upstream testing focuses on early development stages, while downstream testing validates final product functionality.

• Upstream testing occurs during the initial phases of software development, such as requirements gathering and design.

• Downstream testing takes place after the software is developed, focusing on integration, system, and user acceptance testing.

• Example of upstream testing: Reviewing requirements documents to ensure they are clear and testable.

• Example of downstream...read more

Manual test cases for WhatsApp security features

• Verify end-to-end encryption is enabled for all messages

• Test two-factor authentication setup and login process

• Check for secure storage of user data on the device

• Test for secure transmission of media files

• Verify the effectiveness of blocking and reporting features

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

Write integration testcases for A-->B-->C microservices

• Test the communication between A and B microservices

• Test the data flow from B to C microservices

• Verify the response of C microservice based on input from A

• Check for error handling and edge cases in the integration flow

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

Yes, Postman supports data driven testing through the use of variables and data files.

• Postman allows users to define variables and use them in requests for data driven testing.

• Data files such as CSV or JSON can be imported into Postman to drive test data.

• Iterations can be set up in Postman to run tests with different data sets.

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

Identify missing numbers in an integer array using various methods.

• Use a set to track numbers: Convert the array to a set and check against the expected range.

• Mathematical approach: Calculate the expected sum of numbers and subtract the actual sum.

• Sorting method: Sort the array and compare each element with its index to find missing numbers.

• Example: For array [1, 2, 4, 6], missing numbers are 3 and 5.

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

XPath expressions use axes to navigate XML documents, selecting nodes based on their relationships.

• Axes define the node set relative to the current node, e.g., 'child', 'parent', 'ancestor'.

• Example: //book/child::title selects all title elements that are children of book elements.

• Example: //book/ancestor::library selects all library elements that are ancestors of book elements.

• Using 'following-sibling', e.g., //h1/following-sibling::p selects all paragraph siblings after h1.

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

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

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

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