50+ Interview Questions and Answers

Multithreading in Java allows concurrent execution of multiple threads.

• Java provides built-in support for multithreading through the java.lang.Thread class.

• Threads can be created by extending the Thread class or implementing the Runnable interface.

• The start() method is used to start a new thread, which calls the run() method.

• Synchronization mechanisms like synchronized blocks and locks can be used to control access to shared resources.

• Java also provides high-level concurrency...read more

Display data of two tables by joining them using a common column.

• Use SQL JOIN statement to combine data from two tables based on a common column.

• Choose the appropriate type of JOIN based on the relationship between the tables.

• Specify the columns to be displayed in the SELECT statement.

• Use aliases to differentiate between columns with the same name in both tables.

• Apply any necessary filters or sorting to the result set.

Method is a named block of code that can be called multiple times, while a block is a group of statements enclosed in curly braces.

• A method has a name and can accept parameters, while a block does not.

• A method can return a value, while a block cannot.

• A method can be called from anywhere in the program, while a block is only accessible within the scope it was defined.

• Example of a method: public int add(int a, int b) { return a + b; }

• Example of a block: if (condition) { int x =...read more

A variable is a container that holds a value. There are different types of variables in programming.

• Variables are used to store data in a program

• They can be assigned different values during runtime

• Types of variables include integers, floats, strings, booleans, and more

• Variables can be declared with a specific data type or left untyped

• Examples: int age = 25, float price = 9.99, string name = 'John Doe'

Circular linked list is a linked list where the last node points back to the first node, forming a circle.

• Allows for efficient traversal from the end of the list to the beginning

• Useful for applications where data needs to be accessed in a circular manner, such as round-robin scheduling

• Can be used to implement a circular buffer in data structures

Multithreading and servlets are important concepts in Java for concurrent programming and web development.

• Multithreading allows multiple threads to run concurrently, improving performance and responsiveness of applications.

• Servlets are Java classes that handle HTTP requests and generate responses, used for web development.

• Multithreading can be used in servlets to handle multiple requests simultaneously.

• However, care must be taken to ensure thread safety and avoid race conditi...read more

Friend function is not a concept in Java.

• Friend function is a concept in C++ where a non-member function can access private and protected members of a class.

• Java does not have the concept of friend function.

• In Java, access to private and protected members of a class is restricted to the class itself and its subclasses.

The 4 basic principles of OOPS are Abstraction, Encapsulation, Inheritance, and Polymorphism.

• Abstraction: Hiding complex implementation details and showing only necessary information.

• Encapsulation: Binding data and functions together and restricting access to them.

• Inheritance: Creating new classes from existing ones, inheriting properties and methods.

• Polymorphism: Ability of objects to take on multiple forms or behaviors.

A class is a blueprint for creating objects in object-oriented programming. An object is an instance of a class.

• A class defines the properties and behaviors of objects.

• An object is a specific instance of a class.

• Classes can be thought of as templates, while objects are the actual instances created from those templates.

• Example: Class 'Car' may have properties like 'color' and 'model', while an object of class 'Car' could be 'red Ferrari'.

Power Pivot is used for data modeling and analysis while Power Query is used for data transformation and cleaning.

• Power Pivot is an Excel add-in used for creating data models and performing complex analysis.

• Power Query is also an Excel add-in used for data transformation and cleaning before analysis.

• Power Pivot can handle large amounts of data and create relationships between tables.

• Power Query can extract data from various sources and transform it into a usable format.

• Both t...read more

Event Emitter is a class in Node.js that allows objects to subscribe to events and be notified when those events occur.

• Event Emitter is a core module in Node.js

• It allows multiple objects to listen for and respond to events

• Objects can emit events using the 'emit' method

• Listeners can be added using the 'on' method

• Example: const EventEmitter = require('events');

Event loop is a mechanism that allows for asynchronous programming by handling events and callbacks.

• Event loop is a single-threaded mechanism used in programming languages like JavaScript to handle asynchronous operations.

• It continuously checks the call stack for any functions that need to be executed, and processes them in a non-blocking manner.

• Event loop allows for efficient handling of I/O operations, timers, and callbacks without blocking the main thread.

• Example: In Node....read more

To get the latest version, check the official website or app store for updates.

• Check the official website or app store for updates

• Look for release notes or changelogs to see what's new

• Consider subscribing to the software's newsletter or social media for announcements

Components in Angular are reusable building blocks that encapsulate HTML, CSS, and TypeScript code.

• Components are the basic building blocks of an Angular application

• Each component consists of a TypeScript class, an HTML template, and a CSS file

• Components help in organizing the application into smaller, reusable pieces

• Components can communicate with each other using @Input and @Output decorators

• Example: AppComponent is the root component in an Angular application

Technical explanation of what?

• Please provide more context or specify the topic

• Without more information, it's difficult to give a meaningful answer

Enum class is a strongly-typed class that defines a set of named constants.

• Enum class is introduced in C++11 to provide type-safe enums.

• It allows defining a set of named constants that can be used as values.

• Each constant in an enum class is treated as a separate type, preventing type mismatches.

• Example: enum class Color { RED, GREEN, BLUE };

• Example: Color c = Color::RED;

Linked list is a data structure that stores elements in a linear order and allows dynamic memory allocation.

• Consists of nodes that contain data and a pointer to the next node

• Can be singly or doubly linked

• Insertion and deletion can be done efficiently

• Traversal is slower compared to arrays

• Examples: stack, queue, hash table

Joins in SQL 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 based on a related column

• Common types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column

Node.js is a runtime environment that allows you to run JavaScript on the server side.

• Node.js uses an event-driven, non-blocking I/O model, making it lightweight and efficient.

• It is built on the V8 JavaScript engine from Google Chrome.

• Node.js allows you to easily build scalable network applications.

• Example: Creating a simple HTTP server in Node.js - const http = require('http'); http.createServer((req, res) => { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hel...read more

DBMS stands for Database Management System. It is a software system that allows users to define, create, maintain and control access to databases.

• DBMS is used to manage large amounts of data efficiently.

• It provides a way to store, retrieve and manipulate data in a structured manner.

• It ensures data integrity and security by providing access control and backup and recovery mechanisms.

• Examples of DBMS include MySQL, Oracle, SQL Server, and MongoDB.

Sorting algorithms arrange data in a specific order.

• Bubble Sort: repeatedly swap adjacent elements if they are in the wrong order

• Selection Sort: find the smallest element and swap it with the first element, repeat for remaining elements

• Insertion Sort: insert each element into its proper place in a sorted subarray

• Merge Sort: divide the array into two halves, sort each half, and merge them together

• Quick Sort: choose a pivot element, partition the array around the pivot, and rec...read more

OOPs is a programming paradigm based on the concept of objects, which can contain data and code.

• OOPs stands for Object-Oriented Programming.

• It focuses on creating objects that interact with each other to solve a problem.

• It includes concepts like inheritance, encapsulation, polymorphism, and abstraction.

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

• Encapsulation is the practice of hiding data and methods within a class.

• Polymorphism allows obje...read more

DAX stands for Data Analysis Expressions and is a formula language used in Power BI, Excel, and SQL Server Analysis Services.

• DAX is used to create custom calculations and aggregations in data models.

• It includes functions for filtering, grouping, and manipulating data.

• There are two types of DAX expressions: calculated columns and measures.

• Calculated columns are computed during data model creation and are stored in the model.

• Measures are computed on the fly during query executi...read more

JavaScript is a versatile programming language used for web development, allowing for dynamic and interactive website functionality.

• JavaScript is the only programming language that can be executed directly in a web browser, making it essential for front-end web development.

• It enables the creation of interactive elements like forms, animations, and dynamic content on websites.

• JavaScript can be used for both client-side and server-side development, making it a versatile languag...read more

JavaScript is a versatile programming language used for creating interactive web pages and web applications.

• JavaScript allows for dynamic and interactive web content.

• It can be used for client-side and server-side development.

• JavaScript has a large and active community, with extensive libraries and frameworks available.

• It is supported by all major web browsers.

• JavaScript can be used for creating games, mobile apps, and desktop applications.

My future goal is to become a senior software developer and eventually a tech lead, leading a team of developers to create innovative solutions.

• Continue learning and improving my technical skills through courses and certifications

• Gain experience in different areas of software development such as front-end, back-end, and mobile development

• Work on challenging projects that push my limits and allow me to grow as a developer

Build in JCL is a job control language statement used to compile and link programs in mainframe environments.

• Build statement is used to compile and link programs in JCL.

• It specifies the program to be compiled and linked, as well as any necessary parameters.

• Example: //BUILD EXEC PGM=IEBGENER,PARM='INPUT=SYSUT1,OUTPUT=SYSUT2'

A build is a version of a software program that is compiled and ready for testing or release.

• A build is created by compiling the source code of a software program.

• It includes all necessary files and dependencies for the program to run.

• Builds can be categorized as debug builds for testing and release builds for distribution.

• Examples: Debug build of an app with logging enabled, Release build of a website ready for deployment.

Swapping numbers without using a temporary variable.

• Use addition and subtraction to swap values

• Use XOR operator to swap values

• Use multiplication and division to swap values

There are various types of databases such as relational, NoSQL, graph, and document-oriented databases.

• Relational databases store data in tables with predefined relationships between them.

• NoSQL databases are non-relational and can handle unstructured data.

• Graph databases store data in nodes and edges, and are useful for complex relationships.

• Document-oriented databases store data in documents, similar to JSON objects.

• Examples include MySQL, MongoDB, Neo4j, and Cassandra.

Threads are lightweight processes that enable multitasking within a single process.

• Threads share the same memory space as the parent process.

• Threads can communicate with each other through shared memory.

• Threads can be created and managed using threading libraries in programming languages.

• Examples of threading libraries include pthreads in C/C++, and threading module in Python.

My strengths include problem-solving, attention to detail, and teamwork. My goal is to continuously improve my skills and contribute to the success of the company.

• Strong problem-solving skills, able to analyze complex issues and find effective solutions

• Attention to detail, ensuring accuracy and quality in all work

• Collaborative team player, able to communicate effectively and work towards common goals

• Goal-oriented mindset, always seeking to improve skills and contribute to com...read more

C is a procedural programming language while C++ is an object-oriented programming language.

• C is a procedural language, focusing on functions and procedures.

• C++ is an object-oriented language, allowing for classes, objects, and inheritance.

• C++ is an extension of C, adding features like classes, templates, and exception handling.