100+ Infosys Software Developer Interview Questions and Answers

Types of streams in Node.js include Readable, Writable, Duplex, and Transform streams.

• Readable streams allow reading data from a source.

• Writable streams allow writing data to a destination.

• Duplex streams allow both reading and writing.

• Transform streams modify data as it is being read or written.

• Example: fs.createReadStream() creates a Readable stream for reading a file.

REST API is a type of web service that allows communication between different systems over HTTP using standard methods like GET, POST, PUT, DELETE.

• REST stands for Representational State Transfer

• Uses standard HTTP methods like GET, POST, PUT, DELETE for communication

• Data is transferred in JSON or XML format

• Stateless communication between client and server

• Example: GET request to retrieve user data from a server

A hashtable is a data structure that stores key-value pairs and allows for quick retrieval of values based on their keys.

• Uses a hash function to map keys to indexes in an array

• Provides constant time complexity for insertion, deletion, and retrieval operations

• Commonly used in programming languages like Java and Python for implementing dictionaries or maps

Streams are used for processing elements from a data source sequentially, while collections are used for storing and managing groups of objects.

• Streams are lazy and can be processed in parallel, while collections are eager and store all elements in memory.

• Streams support functional-style operations like map, filter, and reduce, while collections provide methods like add, remove, and contains.

• Example: List names = Arrays.asList("Alice", "Bob", "Charlie"); Stream stream = names...read more

Static binding is resolved at compile time, while dynamic binding is resolved at runtime.

• Static binding is also known as early binding, while dynamic binding is also known as late binding.

• Static binding is faster as it is resolved at compile time, while dynamic binding is more flexible as it is resolved at runtime.

• Example of static binding: method overloading, where the compiler determines which method to call based on the method signature.

• Example of dynamic binding: method o...read more

A queue is a data structure that follows the First-In-First-Out (FIFO) principle.

• Elements are added to the back of the queue and removed from the front.

• Common operations include enqueue (add to back) and dequeue (remove from front).

• Used in many applications such as job scheduling, message passing, and breadth-first search.

• Examples of queue implementations include arrays, linked lists, and circular buffers.

An end tag is used to mark the end of an HTML element.

• It is written as

• It is used to close an opening tag

• It is important for proper HTML syntax and rendering

Array in COBOL is a collection of data items of the same type that are stored under a single name.

• Arrays in COBOL are declared using the OCCURS clause.

• The OCCURS clause specifies the number of times the data item occurs in the array.

• Arrays can be one-dimensional or multi-dimensional.

• Array elements are accessed using an index number.

• COBOL arrays can be initialized with default values using the VALUE clause.

A stack is a data structure that follows the Last-In-First-Out (LIFO) principle.

• Elements are added to the top of the stack and removed from the top.

• Common operations include push (add element) and pop (remove element).

• Stacks are used in programming for function calls, expression evaluation, and more.

Use the length property to find the number of elements in an array or characters in a string.

• Access the length property of the array or string to get the count.

• For example, array.length will give the number of elements in the array.

• Similarly, string.length will give the number of characters in the string.

Polymorphism is the ability of a function or method to behave differently based on the object it is called with.

• 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: Animal class with methods like eat() can be inherited by Dog and Cat classes which can override the eat() method to behave differently.

SQL stands for Structured Query Language, used for managing and manipulating relational databases.

• SQL is a standard language for accessing and manipulating databases.

• It is used to perform tasks such as querying data, updating data, and creating databases.

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

• Example: SELECT * FROM employees WHERE department = 'IT';

Python is a high-level programming language known for its simplicity and readability.

• Python is an interpreted language, meaning code is executed line by line.

• It supports multiple programming paradigms like object-oriented, imperative, and functional programming.

• Python has a large standard library and a vibrant community, making it easy to find resources and support.

• Example: print('Hello, World!') is a simple Python program that prints 'Hello, World!' to the console.

A linked list is a linear data structure where elements are stored in nodes with each node pointing to the next node in the sequence.

• Consists of nodes connected by pointers

• Can easily insert or delete elements without shifting other elements

• Types include singly linked list, doubly linked list, and circular linked list

Routing in Angular allows navigation between different components in a single-page application.

• Use RouterModule to set up routes in Angular.

• Define routes in app-routing.module.ts.

• Use routerLink directive in HTML to navigate between components.

• Use ActivatedRoute to access route parameters.

• Lazy loading modules for better performance.

Waterfall model is a linear sequential software development process where progress flows in one direction like a waterfall.

• Sequential process with distinct phases: requirements, design, implementation, testing, deployment

• Each phase must be completed before moving on to the next

• No overlapping of phases

• Changes are difficult to implement once a phase is completed

• Example: Traditional software development lifecycle

I have 3 years of experience as a Software Developer in my previous company.

• Developed web applications using Java, Spring, and Angular

• Worked on database design and optimization using MySQL

• Collaborated with cross-functional teams to deliver projects on time

COND is a JCL statement used to specify the conditions under which a job or step should be executed.

• COND can be used to specify whether a job or step should be executed based on the return code of a previous step or job.

• COND can be set to 'ONLY' to indicate that the job or step should only be executed if the specified condition is met.

• COND can be set to 'EXCEPT' to indicate that the job or step should not be executed if the specified condition is met.

• COND can be used in conju...read more

Object-Oriented Programming (OOP) concepts in Java

• Encapsulation: wrapping data and methods into a single unit

• Inheritance: creating new classes from existing ones

• Polymorphism: ability of objects to take on multiple forms

• Abstraction: hiding implementation details from users

• Interfaces: defining a set of methods that a class must implement

• Classes: blueprint for creating objects

The question is not specified.

• Please provide the question to answer.

• Examples cannot be given without the question.

Java8 introduced new features like lambda expressions, streams, and functional interfaces.

• Lambda expressions allow functional programming in Java.

• Streams provide a way to process collections of data in a functional way.

• Functional interfaces allow the use of lambda expressions as method arguments.

• Default methods allow interfaces to have method implementations.

• Date and Time API provides a more comprehensive way to handle date and time.

• Nashorn JavaScript engine allows Java to in...read more

OOPs (Object-Oriented Programming) is a programming paradigm based on the concept of objects, which can contain data and code.

• OOPs focuses on creating objects that interact with each other to solve problems

• Key principles of OOPs include encapsulation, inheritance, polymorphism, and abstraction

• Encapsulation refers to bundling data and methods that operate on the data into a single unit (object)

• Inheritance allows a class (subclass) to inherit properties and behavior from anothe...read more