300+ ExpertCallers Interview Questions and Answers

Create a shopping application with add to cart, increase/decrease quantity, and update functionality.

• Implement add to cart functionality when clicking on each item

• Update the product listing component to show increase/decrease quantity buttons and the quantity of the item in the cart

• Implement functionality to increase the quantity of an item in the cart

• Implement functionality to decrease the quantity of an item in the cart

• Handle scenarios when the cart quantity is 1 or greater...read more

The question asks to implement a data structure called 'MapSum' with functions to initialize, insert key-value pairs, and find the sum of values with a given prefix.

• Implement a class called 'MapSum' with a constructor to initialize the data structure.

• Implement the 'insert' function to insert key-value pairs into the 'MapSum'. If a key is already present, replace its value with the new one.

• Implement the 'sum' function to find the sum of values whose key has a prefix equal to t...read more

The task is to reverse a given string containing alphanumeric and special characters.

• Iterate through the string from the last character to the first character

• Append each character to a new string to get the reversed string

• Return the reversed string as the output

Machine intelligence refers to the ability of machines to learn and make decisions without explicit programming.

• Machine intelligence involves the use of algorithms and statistical models to enable machines to learn from data and make predictions or decisions.

• Google Assistant is an example of machine intelligence, as it uses natural language processing and machine learning to understand and respond to user queries.

• Other examples of machine intelligence include self-driving car...read more

This interview question covers various topics in Java programming, including OOP concepts, inheritance, keywords, and implementing mathematical algorithms.

• OOP concepts include encapsulation, inheritance, polymorphism, and abstraction.

• Inheritance allows a class to inherit properties and methods from another class.

• To prevent inheritance in Java, use the 'final' keyword before the class declaration.

• Sealed, final, and static are keywords in Java with different functionalities.

• Imp...read more

Selenium components include Selenium IDE, Selenium RC, Selenium WebDriver. Different locators are ID, Name, Class Name, Tag Name, Link Text, Partial Link Text, CSS Selector and XPath. Selenium WebDriver is a tool used to automate web application testing. XPath is a language used to navigate through XML documents and web pages.

• Selenium components: Selenium IDE, Selenium RC, Selenium WebDriver

• Different locators: ID, Name, Class Name, Tag Name, Link Text, Partial Link Text, CSS ...read more

IDisposable is an interface used to release unmanaged resources.

• It is used to release unmanaged resources like file handles, database connections, etc.

• It has a single method called Dispose() which is used to release the resources.

• It is implemented by classes that use unmanaged resources and needs to be disposed of.

• Example: SqlConnection class implements IDisposable to release the database connection.

• Example: FileStream class implements IDisposable to release the file handle.

SOLID is a set of principles for object-oriented programming to make software more maintainable and scalable.

• S - Single Responsibility Principle

• O - Open/Closed Principle

• L - Liskov Substitution Principle

• I - Interface Segregation Principle

• D - Dependency Inversion Principle

• Example: Using Single Responsibility Principle to separate UI and business logic

• Example: Using Open/Closed Principle to extend functionality without modifying existing code

Exceptions in Spring Boot can be handled using @ExceptionHandler annotation and ResponseEntity class.

• Use @ExceptionHandler annotation to handle exceptions in a specific controller or globally

• Use ResponseEntity class to return a custom error message and HTTP status code

• Use try-catch block to handle exceptions in service layer

• Use @ControllerAdvice annotation to handle exceptions globally across all controllers

• Use @ResponseStatus annotation to set a default HTTP status code for ...read more

Code to find the occurrence of a character in a string.

• Iterate through the string and check each character against the target character.

• Use a loop to count the number of occurrences.

• Consider using built-in functions like count() or find().

Concatenate the values in the given integer array with comma.

• Convert the integer array to string array using Arrays.toString()

• Use String.join() method to concatenate with comma

Inheritance, abstract class, override, and interface are all concepts in object-oriented programming.

• Inheritance allows a class to inherit properties and methods from another class.

• Abstract classes cannot be instantiated and are used as a blueprint for other classes.

• Override is used to provide a new implementation for a method that is already defined in a parent class.

• Interfaces define a set of methods that a class must implement.

• All of these concepts are used to create modul...read more

PHP caching, session handling, and API token security

• PHP caching techniques include opcode caching, data caching, and query caching

• Session handling in PHP involves creating a unique session ID for each user and storing session data on the server

• To prevent token hijacking in APIs, use HTTPS, set expiration times for tokens, and use token revocation

• Other security measures include input validation, output encoding, and using secure coding practices

Dependency Injection is a design pattern that allows objects to receive dependencies rather than creating them internally.

• Dependency Injection is used to reduce tight coupling between software components.

• It allows for easier testing and maintenance of code.

• There are three types of Dependency Injection: Constructor Injection, Setter Injection, and Interface Injection.

• Frameworks like Spring and Angular provide built-in support for Dependency Injection.

To convert JSON object to string, use JSON.stringify(). To convert string to JSON object, use JSON.parse().

• JSON.stringify() method converts a JavaScript object or value to a JSON string.

• JSON.parse() method parses a JSON string and returns a JavaScript object.

• Example: var obj = {name: 'John', age: 30}; var jsonString = JSON.stringify(obj); var jsonObj = JSON.parse(jsonString);

• Make sure the JSON string is valid, else it will throw an error.

Answering questions related to Robot Framework and its standard libraries, architecture, setup and teardown, and a sample login script.

• Standard libraries in Robot Framework include BuiltIn, Collections, DateTime, Dialogs, OperatingSystem, Process, Screenshot, String, Telnet, and XML.

• Robot Framework architecture consists of test cases, test suites, and keywords.

• Setup and teardown are pre and post conditions for test cases.

• Sample login script using Robot Framework:

• Open Browser ...read more

No, abstract classes cannot be instantiated.

• Abstract classes are incomplete and cannot be instantiated on their own.

• They can only be used as a base class for other classes.

• Instantiation of an abstract class will result in a compile-time error.

• However, concrete classes that inherit from the abstract class can be instantiated.

Program to find elements of a list with least difference in Python

• Sort the list

• Find the minimum difference between adjacent elements

• Return the elements with minimum difference

Demonetisation in India was a bold move with mixed results.

• Demonetisation aimed to curb black money, corruption and counterfeit currency.

• It caused inconvenience to the common people, especially those in rural areas.

• The move led to a temporary slowdown in the economy.

• Digital transactions and tax compliance increased.

• However, the amount of black money recovered was not significant.

• The informal sector and small businesses were hit hard.

• Overall, demonetisation had both positive a...read more

Constructors and destructors are special methods used in object-oriented programming languages to initialize and destroy objects.

• Constructors are used to initialize objects when they are created.

• Destructors are used to clean up resources used by an object when it is destroyed.

• Constructors have the same name as the class and are called automatically when an object is created.

• Destructors have the same name as the class preceded by a tilde (~) and are called automatically when a...read more

Store procedures, indexes, and virtual tables are important features of MySql.

• Store procedures are pre-written code blocks that can be executed on demand.

• Indexes are used to speed up database queries by creating a quick lookup table.

• Virtual tables are temporary tables that are created on the fly and do not persist in the database.

• Examples of store procedures include creating a new user or updating a record.

• Examples of indexes include primary keys, unique keys, and full-text i...read more

Code to check if two strings are anagram or not

• An anagram is a word or phrase formed by rearranging the letters of a different word or phrase

• To check if two strings are anagram, we can sort both strings and compare them

• Alternatively, we can use a hash table to count the frequency of each character in both strings and compare the counts

Remove duplicate objects from an array of multiple objects.

• Create a new array to store unique objects

• Loop through the original array and check if the object already exists in the new array

• If not, add it to the new array

• Return the new array

AI stands for Artificial Intelligence. It is a branch of computer science that focuses on creating intelligent machines.

• AI is the simulation of human intelligence in machines that are programmed to think and learn like humans.

• It involves the development of algorithms and models that enable machines to perform tasks that typically require human intelligence.

• AI can be used in various fields such as healthcare, finance, transportation, education, and entertainment.

• In healthcare,...read more

We used the Model-View-Controller (MVC) design pattern in our application.

• MVC separates the application into three interconnected components: the model, the view, and the controller.

• The model represents the data and business logic of the application.

• The view displays the data to the user.

• The controller handles user input and updates the model and view accordingly.

• MVC promotes separation of concerns and modularity.

• Example: Our web application uses AngularJS as the front-end fr...read more

Comparator is used to compare objects of different classes while Comparable is used to compare objects of the same class.

• Comparator is an interface that needs to be implemented to compare objects of different classes.

• Comparable is an interface that needs to be implemented to compare objects of the same class.

• Comparator uses compare() method while Comparable uses compareTo() method.

• Comparator can be used to sort a collection in any order while Comparable can only sort in natur...read more

Serialisation is the process of converting an object into a format that can be easily stored or transmitted.

• Serialisation is used in data storage and transmission, allowing objects to be saved to a file or sent over a network.

• It is commonly used in programming languages to convert objects into a byte stream for storage or communication.

• Examples include saving an object to a file in JSON or XML format, or sending an object over a network using protocols like HTTP.

Answers to interview questions for Software Engineer Trainee

• Primary foreign key is a column in a table that is used to link to the primary key of another table

• ACID properties are Atomicity, Consistency, Isolation, and Durability which ensure database transactions are reliable

• To return 3rd maximum salary, use the LIMIT and OFFSET clauses in SQL

• SQL join is used to combine data from two or more tables based on a related column

• IN in SQL is used to specify multiple values in a WHE...read more

Answers to common Selenium interview questions.

• Locators in Selenium are used to identify web elements on a web page. Examples include ID, class name, name, tag name, link text, and partial link text.

• driver.quit() closes the entire browser window and ends the WebDriver session, while driver.close() only closes the current window or tab.

• Implicit wait is a global wait that applies to all web elements and waits for a specified amount of time before throwing an exception if the el...read more

GlobalLogic is a digital product engineering company that provides software development and design services.

• GlobalLogic was founded in 2000 and has over 16,000 employees in 30+ locations worldwide.

• They work with companies in various industries such as automotive, healthcare, and finance.

• Their services include product engineering, digital transformation, and customer experience design.

• Some of their clients include Reuters, Philips, and Qualcomm.

• As for my self introduction, my ...read more

Cash flow statement is a financial statement that shows the inflows and outflows of cash in a business over a specific period of time.

• It provides information on how well a company manages its cash position.

• It consists of three main sections: operating activities, investing activities, and financing activities.

• Operating activities include cash received from sales, payments to suppliers, and salaries paid to employees.

• Investing activities include cash spent on purchasing assets...read more

Technical interview questions for Associate Software Engineer position

• To redirect user to a different website without using events, use window.location.replace() method

• To find 7th highest salary from a table in SQL, use subquery or join with itself

• To duplicate tables in SQL, use CREATE TABLE AS or SELECT INTO statement

• Immediately invoked function is a function that is executed as soon as it is defined

• To change array element of array defined by const keyword in JavaScript, use...read more

Interfaces and abstract classes are used for abstraction and defining contracts.

• Interfaces are a collection of abstract methods that define a contract for a class to implement.

• Abstract classes are classes that cannot be instantiated and can have both abstract and concrete methods.

• Interfaces can be implemented by multiple classes, while a class can only inherit from one abstract class.

• Interfaces are used for loose coupling and to achieve multiple inheritance-like behavior.

• Abst...read more

Artificial Intelligence is the simulation of human intelligence in machines.

• AI involves creating intelligent machines that can perform tasks without human intervention

• It includes machine learning, natural language processing, and robotics

• Examples include Siri, Alexa, and self-driving cars

Maintain state by using a global variable or a state management system.

• Use a global variable to store the state and access it whenever needed.

• Use a state management system like Redux or MobX to manage the state.

• Avoid using local variables or closures to store state as they will be lost when the code is repeated.

• Consider using object-oriented programming principles to encapsulate state within objects.

• Use functional programming principles to avoid mutating state directly.

• Consid...read more

To trigger a job in Jenkins, configure a build trigger and specify the source code repository.

• Configure a build trigger such as a schedule or webhook

• Specify the source code repository to pull code from

• Set up any necessary build steps or scripts

• Ensure proper permissions and credentials are set up

• Test the job to ensure it runs successfully

Move all zeroes to left and ones to right in an array

• Iterate through the array from both ends

• Swap the elements if left is 1 and right is 0

• Stop when left and right pointers meet

Full text index is a database index that allows for efficient text-based searching.

• Full text index is used to search for specific words or phrases within a large amount of text data.

• It is commonly used in search engines, document management systems, and social media platforms.

• Full text index can be created on one or more columns of a table in a database.

• It uses techniques such as stemming, stop words, and word proximity to improve search accuracy.

• Examples of databases that su...read more

Lists are a collection of ordered and changeable elements. They have various functions to manipulate the data.

• Lists are created using square brackets []

• They can contain any data type such as strings, integers, or even other lists

• Functions include append(), insert(), remove(), pop(), sort(), and reverse()

• Example: my_list = ['apple', 'banana', 'cherry']

• Example: my_list.append('orange') adds 'orange' to the end of the list

Code migration involves understanding the existing codebase, planning the migration process, translating code to the new language, testing thoroughly, and ensuring compatibility.

• Understand the existing codebase thoroughly to identify dependencies, logic, and functionality.

• Plan the migration process by breaking it down into smaller tasks, setting timelines, and allocating resources.

• Translate the code to the new language by rewriting or using automated tools like transpilers.

• Te...read more

To delete duplicate rows based on key in a table, use the DELETE statement with a subquery.

• Identify the key column(s) that define the uniqueness of a row

• Use the GROUP BY clause to group the rows by the key column(s)

• Use the HAVING clause to filter out the groups that have more than one row

• Use the subquery to select the duplicate rows to be deleted

• Use the DELETE statement with the subquery to delete the duplicate rows

An interface is a collection of abstract methods. Java 8 introduced default and static methods in interfaces.

• Interface is a blueprint for classes to implement its methods

• Java 8 introduced default methods which provide a default implementation for methods in an interface

• Static methods can also be defined in interfaces

• Example: interface MyInterface { void method1(); default void method2() { //default implementation } static void method3() { //static implementation }}

POM stands for Page Object Model. It is a design pattern used in automation testing to create object repositories for web UI elements.

• POM separates the UI elements and the test scripts, making the code more modular and maintainable.

• It helps in reducing code duplication and improves code reusability.

• POM also makes it easier to update the UI elements in case of any changes in the application.

• Implementation of POM involves creating a separate class for each web page, defining th...read more

AI refers to the simulation of human intelligence in machines that are programmed to think and learn.

• Virtual personal assistants like Siri and Alexa

• Recommendation systems like Netflix and Amazon

• Autonomous vehicles like self-driving cars

• Natural language processing used in chatbots

• Image recognition and computer vision technologies

• Fraud detection systems in banking

• AI-powered medical diagnosis and treatment systems

PHP 7 is faster, more secure and has new features compared to PHP 5.

• PHP 7 has improved performance with up to 2x faster execution

• PHP 7 has better error handling and type declarations

• PHP 7 has new operators and functions like spaceship operator and null coalescing operator

• PHP 7 has removed deprecated features like mysql extension

• PHP 7 has improved support for Unicode

• PHP 7 requires 64-bit architecture

• PHP 7 has improved memory usage

• PHP 7 has improved support for anonymous classe...read more

Pointers in C are used to store memory addresses, storage classes determine the scope and lifetime of variables, memory layout refers to how data is organized in memory, endianness refers to byte order, COM stack is a communication protocol.

• Pointers in C are used to store memory addresses of variables.

• Storage classes in C determine the scope and lifetime of variables.

• Memory layout in C refers to how data is organized in memory.

• Endianness in C refers to the byte order of multi...read more

Rest assured is a Java library used for API testing. Types of assertion include status code, response body, and header.

• Rest assured is a popular Java library used for API testing

• It simplifies the process of sending HTTP requests and verifying the response

• Types of assertion include status code, response body, and header

• Status code assertion checks if the response code is as expected

• Response body assertion checks if the response body contains expected values

• Header assertion che...read more

Program to print duplicate characters in a string

• Create a map to store characters and their counts

• Iterate through the string and update the map

• Print characters with count > 1 as duplicates

Memory leakage can cause app crashes and slow performance. It can be avoided by proper memory management and identifying the root cause.

• Avoid creating unnecessary objects

• Release unused resources

• Use memory profiling tools like Android Profiler

• Avoid static references to objects

• Use weak references when necessary

HTML5 is the latest version of HTML with new features and improvements.

• HTML5 supports new elements like

  ,

• HTML5 introduces new APIs like Geolocation, Drag and Drop, Local Storage, Canvas, Video, Audio, etc.

• HTML5 supports multimedia elements without the need for plugins.

• HTML5 has improved semantics, accessibility, and security features compared to HTML.

SQL is a programming language used for managing and manipulating relational databases.

• SQL stands for Structured Query Language.

• It is used to communicate with and manipulate databases.

• SQL can be used to retrieve data, update data, insert data, and delete data from databases.

• Common SQL commands include SELECT, INSERT, UPDATE, DELETE.

• Examples of SQL database systems include MySQL, PostgreSQL, Oracle, SQL Server.

GIT commands and project creation in GIT

• GIT commands: add, commit, push, pull, clone, branch, merge

• To create a project in GIT: initialize a repository, add files, commit changes, create a remote repository, push changes to remote repository

• Example: git init, git add ., git commit -m 'initial commit', create a repository on GitHub, git remote add origin , git push -u origin master

Count occurrences of characters in a string

• Iterate through the string and use a hashmap to store character counts

• Handle both uppercase and lowercase characters separately

• Consider using ASCII values for efficient counting

Answering questions on analytical programs, garbage collection, and use of static and private class and members.

• Analytical programs can manipulate arrays and strings to extract useful information.

• Garbage collection is an automatic process of freeing up memory used by objects that are no longer needed.

• Static and private class and members are used to control access to certain variables and methods within a class.

• Static members are shared across all instances of a class, while p...read more

AI stands for Artificial Intelligence, which refers to the simulation of human intelligence in machines.

• AI is used in various fields such as healthcare, finance, transportation, and entertainment.

• Examples of AI include virtual assistants like Siri and Alexa, self-driving cars, facial recognition technology, and chatbots.

• AI can be categorized into three types: narrow or weak AI, general AI, and super AI.

• AI technologies include machine learning, natural language processing, and...read more

Improve legacy app performance by optimizing code, implementing caching, and scaling resources.

• Optimize code by identifying and removing bottlenecks

• Implement caching to reduce database calls and improve response time

• Scale resources by using containers or serverless architecture

• Use asynchronous processing for long-running tasks

• Upgrade hardware or infrastructure if necessary

Fall fast refers to failing quickly and early in the development process, while fall safe refers to implementing safety measures to prevent failures.

• Fall fast involves identifying and addressing issues early on in the development cycle.

• Fall safe involves implementing safety measures such as error handling and redundancy to prevent failures.

• An example of fall fast is using automated testing to catch bugs early in the development process.

• An example of fall safe is implementing ...read more

Alerts can be handled using automation tools and screenshots can be captured using built-in functions or third-party libraries.

• Use automation tools like Selenium or Appium to handle alerts in web or mobile applications respectively.

• For capturing screenshots, use built-in functions like 'screenshot' in Selenium or third-party libraries like 'Puppeteer' in Node.js.

• Save the screenshots with appropriate names and in a designated folder for easy access and reference.

• Include the ca...read more

Application Load Balancer and Network Load Balancer are two types of load balancers used in cloud computing.

• Application Load Balancer operates at the application layer and is used to distribute traffic to multiple targets based on the content of the request.

• Network Load Balancer operates at the transport layer and is used to distribute traffic to multiple targets based on IP protocol data.

• Application Load Balancer supports HTTP/HTTPS protocols and can route traffic based on U...read more

CMD and ENTRYPOINT are used to define the default command to run in a container. ADD and COPY are used to add files to a container.

• CMD is used to specify the default command to run when a container is started. It can be overridden by passing a command to docker run.

• ENTRYPOINT is similar to CMD, but it is not overridden by passing a command to docker run. It is used to define the main command that should be run in the container.

• ADD and COPY are used to add files to a container...read more

Utilize problem-solving techniques and communicate bad results professionally to clients.

• Analyze the scenario to identify root causes

• Develop a plan of action to address the issue

• Communicate openly and honestly with the client

• Provide alternative solutions if possible

• Offer support and assistance in implementing the resolution

• Follow up with the client to ensure satisfaction

Fact and dimension are two types of data in a data warehouse.

• Fact is a measurable event that can be analyzed, while dimension provides context to the fact.

• Fact is quantitative, while dimension is qualitative.

• Fact is stored in a fact table, while dimension is stored in a dimension table.

• Examples of fact include sales, revenue, and profit, while examples of dimension include time, location, and product.

• Fact and dimension are used in data modeling to create a star schema or snow...read more

SCDs are used to track changes in data over time. There are three types: Type 1, Type 2, and Type 3.

• Type 1 SCDs overwrite old data with new data.

• Type 2 SCDs add a new row for each change, with a start and end date.

• Type 3 SCDs add columns to the existing row to track changes.

• SCDs are commonly used in data warehousing and business intelligence.

• The choice of SCD type depends on the specific use case and data requirements.

Java is a high-level programming language known for its portability, security, and object-oriented features.

• Java is platform-independent, meaning it can run on any device with a Java Virtual Machine (JVM).

• It is object-oriented, allowing for the creation of reusable code through classes and objects.

• Java is known for its security features, such as sandboxing and encryption.

• It supports multithreading, allowing for concurrent execution of multiple tasks.

• Java has a rich standard l...read more

Quick sort is a sorting algorithm that uses divide and conquer approach to sort an array or list.

• It selects a pivot element and partitions the other elements into two sub-arrays, according to whether they are less than or greater than the pivot.

• It then recursively sorts the sub-arrays.

• It is a very efficient sorting algorithm with an average time complexity of O(n log n).

A knowledge box is a tool used to organize and store information for easy access and retrieval.

• It can be physical or digital

• It can contain information on a specific topic or subject

• It can be used for personal or professional purposes

• Examples include a file cabinet, a computer folder, or a wiki page

Outer join returns all records from one table and matching records from another, while inner join returns only matching records.

• Outer join uses the (+) symbol in Oracle and LEFT/RIGHT OUTER JOIN in SQL Server

• Inner join uses INNER JOIN keyword in SQL

• Sample data: Table A has 5 records, Table B has 3 records, Outer join returns 8 records while Inner join returns 3 records