50+ Klikks Innovations Interview Questions and Answers

The output will depend on the implementation of the method.

• The method may or may not modify the value of the int parameter.

• The method may or may not return a value based on the int parameter.

• Without knowing the implementation of the method, it is impossible to predict the output.

ArrayList and LinkedList are both data structures used to store and manipulate collections of objects in Java.

• ArrayList is implemented as a resizable array, while LinkedList is implemented as a doubly linked list.

• ArrayList provides constant time access to elements using their index, while LinkedList provides constant time insertion and deletion of elements.

• Spring Boot annotations include @Controller, @Service, @Repository, @Autowired, @RequestMapping, and more.

• Lambda expressi...read more

Components used in deploying previous projects in AWS

• Amazon EC2 instances

• Amazon S3 buckets

• Amazon RDS databases

• Elastic Load Balancers

• Auto Scaling Groups

• Amazon CloudFront

• AWS Lambda functions

• Amazon ECS containers

Truncate removes all data from a table while delete removes specific rows.

• Truncate is faster than delete as it doesn't log individual row deletions

• Truncate resets auto-increment values while delete doesn't

• To truncate a table in MySQL, use the TRUNCATE TABLE statement

• Methodology used in my project was Agile

OOP stands for Object-Oriented Programming, a programming paradigm based on the concept of objects.

• OOP focuses on creating objects that contain both data and methods to manipulate that data.

• Encapsulation, inheritance, and polymorphism are key principles of OOP.

• Example: In a library management system, you could have objects like Book, Patron, and Library.

• Example: Inheritance allows a FictionBook class to inherit properties from a Book class.

Pre-defined interfaces in Java are interfaces provided by Java itself, such as Comparable and Serializable.

• Pre-defined interfaces in Java are interfaces provided by Java itself for common functionalities.

• Examples include Comparable, Serializable, Cloneable, etc.

• Prediacate is a functional interface in Java used for boolean-valued functions of one argument.

• SQL query to find 3rd highest salary of employees: SELECT DISTINCT salary FROM employees ORDER BY salary DESC LIMIT 2,1

There is no such thing as upper join or low join in software engineering.

• There is no concept of upper join or low join in software engineering.

• It is possible that the interviewer meant inner join or outer join.

• Inner join returns only the matching rows from both tables while outer join returns all rows from both tables.

• Examples of SQL queries with inner join and outer join can be given.

Collection framework is a set of classes and interfaces that provide a standard way to store and manipulate groups of objects. HashSet is a collection class that implements the Set interface.

• Collection framework provides classes like List, Set, Map for storing and manipulating data.

• HashSet is a collection class that stores unique elements and does not maintain insertion order.

• Example: HashSet set = new HashSet(); set.add("apple"); set.add("banana");

Yes, DML statements can be written in functions.

• Functions can contain DML statements like INSERT, UPDATE, DELETE.

• Functions can also return values based on the DML statements executed.

• However, functions cannot be used to execute DDL statements like CREATE or ALTER.

Use a publish-subscribe pattern to call from one upstream to several downstream

• Implement a publish-subscribe pattern where the upstream component publishes events and the downstream components subscribe to those events

• Use a message broker or event bus to facilitate communication between the upstream and downstream components

• Ensure that the events published by the upstream component are received by all the subscribed downstream components

Visual Studio provides tools for memory management, identifying unused variables and removing unnecessary code.

• Visual Studio's built-in memory profiler helps identify memory leaks and optimize memory usage.

• The Code Analysis tool can detect unused variables and suggest code improvements.

• The Code Cleanup feature can automatically remove unnecessary code and format the codebase.

• Visual Studio also supports third-party extensions like ReSharper for advanced code analysis and clean...read more

Architect an authentication and authorization module

• Identify the user roles and permissions

• Choose an appropriate authentication mechanism (e.g. OAuth, JWT)

• Implement secure password storage and retrieval

• Use encryption for sensitive data

• Implement session management and token expiration

• Integrate with existing user management systems if applicable

I have 5 years of experience working with Selenium using Java.

• 5 years of hands-on experience with Selenium and Java

• Proficient in writing automated test scripts using Selenium WebDriver and Java

• Experience in test automation frameworks like TestNG and JUnit

• Familiar with handling dynamic web elements, synchronization, and handling pop-ups

• Knowledge of integrating Selenium tests with CI/CD pipelines

Performance testing ensures software meets speed, stability, and scalability requirements.

• Performance testing identifies bottlenecks and measures response time, throughput, and resource utilization.

• It helps optimize system performance, improve user experience, and prevent crashes under high load.

• Examples include load testing, stress testing, and endurance testing.

• Performance testing should be conducted throughout the software development life cycle.

• It is important to use real...read more

To inherit a partial class, use the 'partial' keyword in both the base and derived classes.

• Use the 'partial' keyword in both the base and derived classes

• Ensure that the partial classes have the same name and are in the same namespace

• Add the necessary code to the derived class to inherit the properties and methods from the base class

To fetch a record from a table, use SELECT statement with appropriate conditions.

• Use SELECT statement with appropriate columns and table name

• Add conditions using WHERE clause to filter the record

• Use LIMIT clause to limit the number of records returned

• Example: SELECT * FROM users WHERE id = 1 LIMIT 1

Hoisting in JavaScript refers to the behavior where variable and function declarations are moved to the top of their containing scope during compilation. Aggregation in MongoDB is the process of combining data records and expressing them in a summarized form.

• Hoisting in JavaScript allows you to use a variable or function before it is declared, as long as it is declared somewhere in the scope.

• Aggregation in MongoDB involves operations like grouping, summing, averaging, and sor...read more

Boomi document types include XML, JSON, flat file, and database record.

• XML

• JSON

• Flat file

• Database record

Middleware in .NET Core is software components that are assembled into the pipeline to handle requests and responses.

• Middleware components are executed in the order they are added to the pipeline.

• They can perform tasks such as authentication, logging, error handling, etc.

• Examples of middleware in .NET Core include UseAuthentication, UseMvc, UseStaticFiles, etc.

Annotation used to mark a class as a Spring Boot application.

• Used to indicate the main class of a Spring Boot application

• Enables auto-configuration and component scanning

• Can be used with additional annotations like @SpringBootApplication

Query to find 2nd highest salary in a table

• Use a subquery to select distinct salaries

• Order the salaries in descending order

• Use LIMIT to get the second highest salary

Middleware is software that acts as a bridge between different applications or components. Express is a web application framework for Node.js.

• Middleware is software that handles communication between different systems or components

• Express is a popular web application framework for Node.js

• Express simplifies the process of building web applications by providing a set of features and tools

• Middleware in Express can be used for tasks like authentication, logging, and error handlin...read more

Joins are used to combine rows from two or more tables based on a related column between them.

• Types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• INNER JOIN returns rows when there is at least one match in both tables.

• LEFT JOIN returns all rows from the left table and the matched rows from the right table.

• RIGHT JOIN returns all rows from the right table and the matched rows from the left table.

• FULL JOIN returns rows when there is a match in one of the tabl...read more

My expected CTC is in line with industry standards and commensurate with my experience and skills.

• Research industry standards and salary ranges for the position and location

• Consider my experience, skills, and qualifications

• Negotiate based on the company's compensation package and benefits

• Provide a range rather than a specific number

Spring Boot allows multiple database connections through configuration and using multiple data sources.

• Configure multiple data sources in application.properties or YAML file

• Create separate DataSource and JdbcTemplate beans for each data source

• Use @Qualifier annotation to specify which data source to use in a repository or service

• Example: https://www.baeldung.com/spring-data-jpa-multiple-databases

The 'using' keyword is used in C# to declare a code block that uses an object and automatically disposes of it when done.

• The 'using' keyword is followed by a set of parentheses that contain the object to be used.

• The object must implement the IDisposable interface.

• The 'using' block ensures that the object is disposed of when the block is exited, even if an exception is thrown.

• Example: using (FileStream fileStream = new FileStream("file.txt", FileMode.Open)) { // code that uses...read more

WebAPIs allow communication between different systems and enable access to data and functionality over the internet.

• WebAPIs provide a standardized way for different systems to communicate with each other over the internet.

• They allow access to data and functionality from remote servers, enabling the creation of web and mobile applications.

• WebAPIs can be used to integrate different systems, such as payment gateways, social media platforms, and third-party services.

• Examples of p...read more

SQL statement using upper join

• Use the UPPER function to convert the join condition to uppercase

• Join two tables using the converted join condition

• Example: SELECT * FROM table1 JOIN table2 ON UPPER(table1.column) = UPPER(table2.column)

Abstract class can have both abstract and non-abstract methods, while interface can only have abstract methods.

• Abstract class can have constructors, fields, and methods, while interface cannot have any implementation.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Abstract classes are used to define a common behavior for subclasses, while interfaces are used to define a contract for classes to implement.

• Example: Abstract class - Animal w...read more

Triggers in SQL are special types of stored procedures that are automatically executed in response to certain events.

• Triggers can be used to enforce business rules or data integrity

• They can be executed before or after an INSERT, UPDATE, or DELETE statement

• Triggers can also be used to audit changes to data

• Examples of triggers include sending an email notification when a new record is inserted or updating a related table when a record is deleted

A final variable in Java is a variable that cannot be reassigned once it has been initialized.

• Final variables are declared using the 'final' keyword.

• They can be assigned a value only once.

• Final variables are often used to represent constants or values that should not be changed.

• They can be declared at the class, method, or block level.

• Final variables can be used in method parameters, local variables, instance variables, or class variables.

Boomi Atomsphere is a cloud-based integration platform that allows businesses to connect applications, data, and devices across on-premises and cloud environments.

• Integration platform for connecting applications, data, and devices

• Cloud-based solution for on-premises and cloud environments

• Supports API management, data integration, and workflow automation

• Provides pre-built connectors for popular applications and systems

• Allows for real-time monitoring and management of integrati...read more

Agile methodology is an iterative approach to software development that emphasizes flexibility and customer satisfaction.

• Agile values individuals and interactions over processes and tools

• It emphasizes working software over comprehensive documentation

• It involves frequent collaboration with customers and stakeholders

• It encourages adapting to changing requirements and feedback

• Examples of Agile methodologies include Scrum, Kanban, and Extreme Programming (XP)

final, finally, and finalize are related to Java programming language.

• final is a keyword used to restrict the user from changing the value of a variable.

• finally is a block of code that is always executed, whether an exception is thrown or not.

• finalize is a method used for cleanup operations before an object is garbage collected.

Polymorphism is the ability of a single function or method to operate on different types of data.

• Polymorphism allows objects of different classes to be treated as objects of a common superclass.

• There are two types of polymorphism: compile-time (method overloading) and runtime (method overriding).

• Example: Inheritance in object-oriented programming languages like Java allows for polymorphism.

Inbuilt methods that follow overriding

• In Java, methods that can be overridden are marked with the 'override' keyword

• The overridden method must have the same name, return type, and parameters as the original method

• The 'super' keyword can be used to call the overridden method from the subclass

• Overriding can be used to provide a different implementation of a method in a subclass

Object-oriented programming paradigm focusing on objects and classes for code organization and reusability.

• Encapsulation: Bundling data and methods that operate on the data into a single unit (class).

• Inheritance: Ability of a class to inherit properties and behavior from another class.

• Polymorphism: Ability to present the same interface for different data types.

• Abstraction: Hiding the complex implementation details and showing only the necessary features of an object.

JVM is the Java Virtual Machine that executes Java bytecode. JRE is the Java Runtime Environment that includes JVM and libraries. JDK is the Java Development Kit that includes JRE and development tools.

• JVM is responsible for running Java programs by interpreting bytecode.

• JRE includes JVM along with libraries and other components needed to run Java applications.

• JDK is a full-featured development kit that includes JRE, development tools, and libraries.

• Example: If you only want ...read more

Code to check if a string is a palindrome or not.

• Create a function that takes a string as input

• Remove all non-alphanumeric characters and convert to lowercase

• Compare the string with its reverse to check if it's a palindrome

Procure to pay process is a series of steps involved in purchasing goods or services from a supplier and making payment for them.

• The process starts with identifying the need for a product or service.

• A purchase requisition is created and sent for approval.

• Once approved, a purchase order is generated and sent to the supplier.

• The supplier delivers the goods or services and an invoice is received.

• The invoice is matched with the purchase order and goods receipt.

• If everything match...read more

A stream is a sequence of data elements made available over time.

• Streams are used for processing large amounts of data efficiently.

• They can be infinite or finite in nature.

• Examples include reading data from a file or network, or generating data dynamically.

Extension methods allow adding functionality to existing types without modifying them.

• Extension methods are defined in a static class.

• They must be marked with the 'this' keyword before the first parameter.

• They can be called on instances of the extended type as if they were instance methods.

• Extension methods can be used to add functionality to third-party or built-in types.

• Example: 'myString.Reverse()' where 'Reverse' is an extension method for the 'string' type.

I have worked on a variety of tech stacks including Java Spring, React, Node.js, and MongoDB.

• Java Spring

• React

• Node.js

• MongoDB

Joins are used to combine rows from two or more tables based on a related column between them.

• Joins are used to retrieve data from multiple tables in a single query.

• Common types of joins are inner join, left join, right join, and full outer join.

• Inner join returns only the matching rows from both tables.

• Left join returns all the rows from the left table and matching rows from the right table.

• Right join returns all the rows from the right table and matching rows from the left ...read more

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

• Kafka uses topics to organize and store data streams.

• Producers publish messages to topics.

• Consumers subscribe to topics to read messages.

• ZooKeeper is used for managing Kafka brokers and maintaining metadata.

• Kafka Connect is used for integrating Kafka with external systems.

• Kafka Streams API allows for building stream processing applications.

• Kafka provides fault toler...read more

Scrum roles are the key positions in a Scrum team responsible for different aspects of the project.

• Product Owner: Represents the stakeholders and defines the product vision.

• Scrum Master: Facilitates the Scrum process and ensures adherence to Scrum principles.

• Development Team: Self-organizing group responsible for delivering the product increment.

• Stakeholders: Individuals or groups with an interest in the project's outcome.

Print a given pattern using array of strings

• Use nested loops to iterate through rows and columns

• Build the pattern by adding characters based on the row and column indices

• Example: For a pattern like '12345', the first row would be '1', second row '12', and so on

Projects are specific tasks or assignments that require a team to work together to achieve a common goal.

• Projects involve a defined scope, timeline, and budget.

• They require a team of individuals with different skills and expertise.

• Examples include developing a new software application, implementing a new system, or conducting a research study.

Comparable is an interface used for natural ordering while Comparator is an interface used for custom ordering.

• Comparable is implemented by the class itself while Comparator is implemented by a separate class.

• Comparable compares 'this' object with the specified object while Comparator compares two different objects.

• Example of Comparable: String, Integer, Double. Example of Comparator: Collections.sort(list, new MyComparator());

Data fragmentation refers to the scattering of data across different locations or storage devices, making it difficult to access or manage.

• Data fragmentation can occur when data is stored in multiple databases or servers.

• It can also happen when data is divided into smaller pieces and stored in different locations.

• Fragmented data can lead to slower access times and increased complexity in managing data.

• Examples include fragmented files on a hard drive or fragmented databases i...read more

Find two numbers in an array that add up to a specific target value.

• Use a hashmap to store the difference between the target value and each element in the array.

• Iterate through the array and check if the current element's complement exists in the hashmap.

• Return the indices of the two numbers that add up to the target value.

A record type is a data type that represents a structured collection of fields or attributes.

• Record types are used to define structured data in programming languages.

• Each field in a record type has a name and a data type.

• Record types are commonly used in database systems to represent rows in tables.

• Examples of record types include structs in C, classes in Java, and tuples in Python.