60+ Nippon Koei India Interview Questions and Answers

I have worked with various design patterns including MVC, Singleton, Factory, and Observer.

• MVC pattern for separating concerns in web applications

• Singleton pattern for ensuring only one instance of a class is created

• Factory pattern for creating objects without exposing the instantiation logic

• Observer pattern for implementing event-driven architectures

String is immutable to ensure thread safety and security. Yes, we can write our own immutable class.

• String is immutable to prevent accidental modification of data.

• Immutable classes ensure thread safety and security.

• We can write our own immutable class by making all fields final and not providing any setters.

• Examples of immutable classes are String, Integer, and LocalDate.

Functional programming focuses on functions while object oriented programming focuses on objects and their interactions.

• Functional programming emphasizes immutability and avoids side effects.

• Object oriented programming uses classes and objects to encapsulate data and behavior.

• Functional programming languages include Haskell and Lisp while object oriented programming languages include Java and C++.

• Functional programming is often used for mathematical computations while object ...read more

Circuit breaker is used to prevent cascading failures in distributed systems.

• Circuit breaker is used to handle faults in microservices architecture.

• It is used to prevent overloading of a service by temporarily stopping requests to it.

• It helps in improving the resilience of the system by handling failures gracefully.

• Example: If a service is down, circuit breaker will stop sending requests to it and will try again after a specified time interval.

• It is also used for monitoring t...read more

I have experience using containerization tools like Docker and Kubernetes for microservices deployment.

• I have used Docker to create container images for each microservice.

• I have used Kubernetes to manage the deployment, scaling, and load balancing of the microservices.

• I have also used Helm charts to package and deploy the microservices as a group.

• I have implemented CI/CD pipelines using tools like Jenkins or GitLab to automate the deployment process.

• I have monitored the micro...read more

JWT tokens are implemented and validated using a combination of server-side and client-side code.

• The server generates a JWT token and sends it to the client upon successful authentication.

• The client stores the token in local storage or a cookie.

• For each subsequent request, the client sends the token in the Authorization header.

• The server verifies the token's signature and expiration time before processing the request.

• If the token is invalid or expired, the server returns a 40...read more

Constructor injection is preferred over Setter injection.

• Constructor injection ensures that all required dependencies are provided at the time of object creation.

• Setter injection allows for optional dependencies and can be used for dynamic changes.

• Constructor injection is more secure as the object is fully initialized before use.

• Setter injection can lead to inconsistent object states if not used carefully.

• Constructor injection is easier to test and maintain.

• Setter injection c...read more

Yes, I have configured saga design pattern in my project.

• I have used saga design pattern to manage complex workflows and transactions.

• I have implemented sagas using libraries like Redux-Saga and NServiceBus.

• I have used sagas to handle scenarios like order processing, payment processing, and inventory management.

• I have also used sagas to handle compensating transactions in case of failures.

A singleton class is a class that can only be instantiated once. It is important to secure it in a multi-threading environment.

• Create a private constructor to prevent external instantiation

• Create a private static instance of the class

• Create a public static method to return the instance

• Use synchronized keyword to ensure thread safety

• Consider using double-checked locking to improve performance

Code to find repeated characters in string with count using Java 8

• Convert string to char array

• Use streams to group by character and count

• Filter out characters with count less than 2

• Print the repeated characters with their count

Orchestration and choreography are design patterns used in distributed systems.

• Orchestration involves a central controller that coordinates the interactions between services.

• Choreography involves services communicating with each other directly without a central controller.

• Orchestration is more suitable for complex workflows while choreography is more flexible.

• Examples of orchestration tools include Kubernetes and Apache Airflow.

• Examples of choreography tools include Apache Ka...read more

Get third highest salary in given employee list using Java 8

• Sort the employee list in descending order of salary using Comparator

• Use distinct() to remove duplicates

• Skip the first two highest salaries using skip()

• Use findFirst() to get the third highest salary

Difference between @Configuration and @Component annotations

• The @Configuration annotation is used to define a configuration class that provides bean definitions

• The @Component annotation is used to mark a class as a Spring component

• Configuration classes can be imported into other configuration classes using @Import annotation

• Components can be scanned and automatically registered as beans using @ComponentScan annotation

Answers to questions asked in a Software Engineer Trainee interview

• 4 pillars of OOPS: Abstraction, Encapsulation, Inheritance, Polymorphism

• Normalization types: 1NF, 2NF, 3NF, BCNF

• Heap tree: complete binary tree, used in heap sort, priority queue

• Quick sort: divide and conquer, worst case O(n^2), best case O(nlogn)

• Merge sort: divide and conquer, always O(nlogn)

• Join types: inner, outer, left, right

• Class and constructor can be made private

• Method is used to perform an action, cons...read more

Yes, I have extensive experience in implementing CI/CD pipelines.

• I have worked with tools like Jenkins, GitLab CI/CD, and Travis CI.

• I have automated build, test, and deployment processes for multiple projects.

• I have integrated code quality checks and security scans into the pipeline.

• I have also implemented blue-green and canary deployment strategies.

• Overall, I understand the importance of continuous integration and delivery in modern software development.

Autowire simplifies dependency injection in Spring by automatically wiring beans together.

• Autowire eliminates the need for manual bean wiring in XML configuration files.

• It reduces the amount of boilerplate code needed to configure dependencies.

• Autowire can be used with different types of injection, such as constructor, setter, and field injection.

• Example: @Autowired private MyService myService; will automatically inject the MyService bean into the field.

• Example: @Autowired pu...read more

We secure our microservices using a combination of authentication, authorization, encryption, and monitoring.

• We use OAuth2 for authentication and authorization.

• We encrypt sensitive data using AES-256 encryption.

• We use SSL/TLS for secure communication between microservices.

• We implement rate limiting to prevent DDoS attacks.

• We monitor our microservices using tools like Prometheus and Grafana.

• We perform regular security audits and penetration testing.

I have used various design patterns such as Singleton, Factory, Observer, and Decorator.

• Singleton pattern was used to ensure only one instance of a class is created.

• Factory pattern was used to create objects without exposing the instantiation logic to the client.

• Observer pattern was used to notify the dependent objects when there is a change in the state of an object.

• Decorator pattern was used to add new functionality to an existing object without altering its structure.

Java8 Stream provides a functional approach to processing collections of objects.

• Allows for functional-style operations on collections like map, filter, reduce

• Supports parallel processing for improved performance

• Lazy evaluation allows for efficient processing of large datasets

• Reduces boilerplate code and promotes cleaner, more concise code

• Example: List names = Arrays.asList("Alice", "Bob", "Charlie"); names.stream().filter(name -> name.startsWith("A")).forEach(System.out::pri...read more

Yes, I am familiar with VPN, Task Manager, and Control Panel. I have used them in various real-life scenarios.

• VPN stands for Virtual Private Network and is used to securely connect to a private network over the internet.

• Task Manager is a system monitor and task manager utility that provides information about the processes and applications running on a computer.

• Control Panel is a centralized hub in Windows operating systems where users can view and adjust system settings.

• I hav...read more

Prevent SQL injection by using parameterized queries and input validation.

• Use parameterized queries instead of concatenating user input with SQL statements

• Sanitize and validate user input before using it in a query

• Limit database privileges for the user account used by the application

• Use prepared statements and stored procedures

• Avoid displaying database error messages to users

Dependency Injection in ASP.NET Core is registered in ConfigureServices method of Startup class.

• Add services.AddSingleton(); for singleton lifetime

• Add services.AddScoped(); for scoped lifetime

• Add services.AddTransient(); for transient lifetime

Indexing is a technique used to optimize the performance of databases by allowing faster retrieval of data.

• Indexing creates a data structure that improves the speed of data retrieval operations in a database.

• It works by creating an index on one or more columns in a table, allowing the database to quickly locate the rows that match a certain condition.

• Examples of indexing include creating indexes on primary keys, foreign keys, and frequently queried columns.

CopyOnWriteArrayList is a thread-safe variant of ArrayList where all mutative operations (add, set, remove, etc) are implemented by making a fresh copy of the underlying array.

• CopyOnWriteArrayList is part of the java.util.concurrent package in Java.

• It is used in scenarios where reads are far more common than writes, as it allows for high read concurrency without the need for synchronization.

• It is particularly useful in situations where you have a large number of reads and onl...read more

To improve performance of a Stored procedure, optimize query, use indexes, minimize data retrieval, and avoid cursors.

• Optimize query by using proper indexing

• Minimize data retrieval by fetching only required columns

• Avoid using cursors for looping through data

• Use SET NOCOUNT ON to stop the message indicating the number of rows affected by a Transact-SQL statement

The content-type for attaching a file in a post request is 'multipart/form-data'.

• The content-type 'multipart/form-data' is used when submitting forms that contain files.

• It allows multiple parts to be combined into a single body, each part representing a different form field or file.

• The 'Content-Disposition' header is used to specify the name of the file being uploaded.

To navigate between different windows in Selenium code, use getWindowHandles() to get all window handles and switchTo() to switch between them.

• Use getWindowHandles() to get all window handles

• Use switchTo() to switch between windows

• Example: Set windowHandles = driver.getWindowHandles(); driver.switchTo().window(windowHandles.toArray()[1]);

Public subnet allows internet access, while private subnet does not.

• Public subnet has a route to the internet gateway, while private subnet does not.

• Instances in public subnet can have public IP addresses, while instances in private subnet cannot.

• Public subnet is typically used for resources that need to be accessed from the internet, while private subnet is used for resources that should not be directly accessible from the internet.

JVM stands for Java Virtual Machine. It is a virtual machine that executes Java bytecode.

• JVM is a part of the Java Runtime Environment (JRE).

• It provides a platform-independent execution environment for Java programs.

• JVM interprets Java bytecode and translates it into machine-specific instructions.

• It manages memory, handles garbage collection, and provides runtime environment for Java applications.

• JVM supports Just-In-Time (JIT) compilation for performance optimization.

• Example...read more

I manage program budgets by closely monitoring expenses and ensuring they align with client expectations.

• Regularly review and update budgets to track expenses and ensure they are within scope

• Communicate with clients to understand their budget constraints and priorities

• Negotiate with vendors to secure competitive pricing and maximize budget efficiency

Read-only variables can be modified by the program, while const variables cannot be changed.

• Read-only variables can be modified by the program during runtime, while const variables cannot be changed at all.

• Using 'const' keyword ensures that the value of the variable remains constant throughout the program.

• Read-only variables are typically used when the value needs to be initialized at runtime, while const variables are used for values that should not change.

• Example: int readO...read more

Agile methodologies offer advantages such as flexibility and adaptability, but require careful management of burnup charts.

• Agile methodologies prioritize collaboration and adaptability over rigid planning and documentation.

• This approach can lead to faster development and more responsive teams.

• However, it also requires careful management of burnup charts to ensure that progress is being made and goals are being met.

• Burnup charts can help teams track progress and identify poten...read more

Yes, JVM is platform independent.

• JVM stands for Java Virtual Machine.

• It provides a runtime environment for executing Java bytecode.

• JVM abstracts the underlying hardware and operating system, making Java programs portable.

• Java programs can run on any platform that has a compatible JVM installed.

• JVM implementations exist for various operating systems, such as Windows, macOS, Linux, etc.

Software testing is the process of evaluating a software application or system to ensure it meets the specified requirements.

• Software testing is done to identify defects or errors in the software.

• It involves executing the software with test cases and comparing the actual results with expected results.

• Testing can be performed at different levels such as unit testing, integration testing, system testing, and acceptance testing.

• Various techniques and tools are used for software ...read more

Abstract classes and interfaces are used in object-oriented programming to define common behavior and structure for classes.

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

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

• Abstract classes can have constructors, while interfaces cannot.

• Example: abstract class Animal { abstract void makeSound(); } interface Flyable { void fly(); ...read more

Active Directory is a directory service developed by Microsoft for Windows domain networks.

• Centralized database for managing network resources

• Stores information about users, computers, and other network objects

• Used for authentication, authorization, and configuration

• Enables single sign-on for users across multiple applications and services

US mortgage life cycle involves origination, underwriting, servicing, and foreclosure.

• Origination involves the borrower applying for a loan and the lender assessing their creditworthiness.

• Underwriting involves verifying the borrower's information and determining the loan amount and terms.

• Servicing involves collecting payments, managing escrow accounts, and handling delinquencies.

• Foreclosure is the legal process of repossessing the property if the borrower defaults on the loan...read more

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

• Inheritance is a fundamental concept in object-oriented programming.

• It promotes code reusability and allows for the creation of hierarchical relationships between classes.

• The class that is being inherited from is called the superclass or parent class, while the class that inherits is called the subclass or child class.

• The subclass can access the public and protected members of the supercla...read more

Data structures are used to organize and store data efficiently in computer memory.

• Data structures like arrays, linked lists, trees, graphs, and hash tables are commonly used in software engineering.

• Arrays are used to store elements of the same data type in contiguous memory locations.

• Linked lists consist of nodes where each node contains data and a reference to the next node.

• Trees are hierarchical data structures with a root node and child nodes.

• Graphs are used to represent ...read more

Recruitment cycle is the process of identifying, attracting, interviewing, selecting, and hiring employees.

• Identifying the need for a new employee

• Creating a job description and posting it on job boards

• Reviewing resumes and conducting interviews

• Selecting the best candidate and making a job offer

• Onboarding the new employee

• Monitoring and evaluating the new hire's performance

To fix a crash in an application, identify the root cause, analyze crash logs, use debugging tools, and test the fix thoroughly.

• Identify the root cause of the crash by analyzing crash logs and user reports.

• Use debugging tools like Xcode's debugger or third-party tools like Crashlytics.

• Implement defensive coding practices to handle edge cases and prevent crashes.

• Test the fix thoroughly on different devices and iOS versions to ensure stability.

• Consider using automated testing t...read more

A protocol extension allows adding functionality to existing types without modifying their original implementation.

• Define a protocol with required methods

• Create an extension for the protocol

• Implement the methods in the extension

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 of compile-time polymorphism: function overloading where multiple functions have the same name but different parameters.

• Example of runtime polymorphism: method overriding wher...read more

Inceptor in Angular is a service that allows intercepting HTTP requests and responses.

• Inceptor is used for modifying requests or responses before they are sent or received.

• It can be used for adding headers, logging, error handling, etc.

• Example: intercepting requests to add authentication token.

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

Dependency Injection is a design pattern in which components are given their dependencies rather than creating them internally.

• Allows for easier testing by providing mock dependencies

• Promotes loose coupling between components

• Improves code reusability and maintainability

• Commonly used in frameworks like Spring in Java

Abstraction focuses on hiding the implementation details while encapsulation bundles the data and methods into a single unit.

• Abstraction allows us to focus on the essential features of an object while hiding the irrelevant details.

• Encapsulation helps in bundling the data and methods that operate on the data into a single unit.

• Abstraction is achieved through abstract classes and interfaces in object-oriented programming.

• Encapsulation helps in achieving data hiding and access c...read more

Adopting new iOS versions involves staying updated, testing compatibility, updating codebase, and utilizing new features.

• Stay updated on new iOS versions and features released by Apple.

• Test compatibility of existing apps with the new iOS version.

• Update the codebase to ensure compatibility and take advantage of new features.

• Utilize new features introduced in the latest iOS version to enhance app functionality.

• Consider redesigning UI/UX to align with the latest iOS design guide...read more

Button hierarchy in Objective-C refers to the order in which buttons are arranged and displayed on the user interface.

• Button hierarchy determines the visual layout and organization of buttons on a screen.

• Buttons can be arranged in a linear or hierarchical manner.

• The hierarchy can be defined using constraints or by using a layout manager.

• Example: A login screen may have a primary button at the bottom and secondary buttons above it.

Swift is a programming language used for iOS, macOS, watchOS, and tvOS development. Primary label of DS is data structure.

• Swift is a statically typed language developed by Apple.

• It is used for developing applications for Apple's platforms.

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

• Examples of data structures include arrays, linked lists, and trees.

SOLID is a set of five design principles to make software designs more understandable, flexible, and maintainable.

• S - Single Responsibility Principle: A class should have only one reason to change.

• O - Open/Closed Principle: Software entities should be open for extension but closed for modification.

• L - Liskov Substitution Principle: Objects of a superclass should be replaceable with objects of its subclasses without affecting the functionality.

• I - Interface Segregation Princip...read more

Multitenancy is a software architecture where a single instance of the software serves multiple customers, known as tenants.

• Allows multiple users (tenants) to access the same application while keeping their data isolated

• Reduces costs by sharing resources among multiple users

• Customization options for each tenant to meet their specific needs

JWT stands for JSON Web Token, a compact and self-contained way for securely transmitting information between parties as a JSON object.

• JWT is commonly used for authentication and information exchange in web development.

• It consists of three parts: header, payload, and signature.

• The header typically consists of the type of token and the signing algorithm being used.

• The payload contains the claims, which are statements about an entity and additional data.

• The signature is used to...read more

Object-oriented programming (OOP) is a programming paradigm that uses objects to represent and manipulate data.

• OOP allows for modular and reusable code.

• It emphasizes encapsulation, inheritance, and polymorphism.

• Java supports OOP through classes, objects, and interfaces.

• Example: Creating a class 'Car' with properties like 'color' and 'speed', and methods like 'start' and 'stop'.

XML top-down approach is a methodology where the structure of an XML document is designed first and then the data is filled in.

• Design the XML structure before populating it with data

• Start with the root element and define child elements and their attributes

• Use XML Schema Definition (XSD) to define the structure and data types

• Create the XML document based on the defined structure

• Populate the XML document with data

Financial aspects of projects involve budgeting, cost estimation, financial tracking, and resource allocation.

• Budgeting is crucial to ensure that the project stays within financial constraints.

• Cost estimation helps in predicting the expenses involved in the project.

• Financial tracking involves monitoring expenses and revenues throughout the project.

• Resource allocation ensures that funds are distributed efficiently to meet project requirements.