20+ Interview Questions and Answers

Java 8 introduced new features like lambda expressions, functional interfaces, and streams. Functional interfaces have a single abstract method. Runnable is a functional interface for running a task in a separate thread, while Callable is a functional interface that can return a result and throw checked exceptions.

• Java 8 introduced lambda expressions for writing concise code.

• Functional interfaces have a single abstract method, such as Runnable or Callable.

• Runnable is a functi...read more

A newspaper application system design involves components like user interface, content management, user authentication, and data storage.

• User interface for reading articles and viewing images/videos

• Content management system for publishing articles, managing categories, and scheduling posts

• User authentication system for login, registration, and profile management

• Data storage for storing articles, images, user data, and analytics

Optimisation techniques are methods used to improve the efficiency and performance of software applications.

• Use of algorithms like dynamic programming to reduce time complexity

• Utilizing data structures like hash tables for faster data retrieval

• Implementing caching mechanisms to store frequently accessed data

• Profiling and analyzing code to identify bottlenecks and optimize them

Loop through both arrays and use a hashmap to store frequency of elements, then find the extra element.

• Loop through both arrays and store frequency of elements in a hashmap

• Compare the frequency of elements in both arrays to find the extra element

• Return the extra element found in the second array

HashMap is a data structure that stores key-value pairs and uses hashing to retrieve values quickly.

• Hashing function is used to convert keys into array indices

• Collisions can occur when multiple keys hash to the same index

• HashMap uses linked lists or binary trees to handle collisions

• Retrieving a value involves hashing the key to find the index and then traversing the linked list or tree

• Insertion and deletion involve similar steps

• HashMap can dynamically resize to maintain a goo...read more

Mutable objects in Python can be created using various methods such as assignment, copy, or using built-in functions like dict() or list().

• Assignment operator can be used to create mutable objects, for example: x = [1, 2, 3]

• Copying an existing mutable object using the copy() method or slicing can create a new mutable object

• Using built-in functions like dict() or list() to create mutable objects

A map can be created using geographic data and software tools to visualize locations and their relationships.

• Gather geographic data such as coordinates, boundaries, and landmarks

• Use mapping software like Google Maps, ArcGIS, or Mapbox to input and visualize the data

• Customize the map with labels, colors, and markers to enhance readability

• Consider the audience and purpose of the map to determine the level of detail and interactivity needed

Use stream api to calculate sum of integers in a list.

• Use stream() method on the list to create a stream of elements.

• Use mapToInt() method to convert each element to an integer.

• Use sum() method to calculate the sum of all integers.

I would react calmly and assess the situation before taking appropriate action.

• Remain calm and composed

• Assess the situation

• Take appropriate action based on the conditions

The code will output 'Hello World!'

• The code is a simple print statement

• It will output the string 'Hello World!'

I will design a scalable and modular architecture that meets the product requirements.

• Identify the key components and their interactions

• Consider scalability and performance requirements

• Use design patterns like MVC or microservices

• Ensure security and data privacy measures are in place

• Document the architecture for future reference

Detect cycle in a linked list using Floyd's Tortoise and Hare algorithm

• Use two pointers, slow and fast, to traverse the linked list

• If there is a cycle, the fast pointer will eventually meet the slow pointer

• Time complexity is O(n) and space complexity is O(1)

Design a database for a travel app to store user information, bookings, reviews, and destinations.

• Create tables for users, bookings, reviews, and destinations

• Include columns for user details, booking information, review ratings, and destination details

• Establish relationships between tables using foreign keys

• Consider indexing commonly queried fields for faster retrieval

• Implement data validation to ensure data integrity

To identify circles collided, check if the sum of their radii is greater than the distance between their centers.

• Calculate the distance between the centers of the two circles using the distance formula

• Add the radii of the two circles

• If the sum of the radii is greater than or equal to the distance between the centers, the circles have collided

I actively participate in requirement gathering processes by collaborating with stakeholders to understand needs and constraints.

• Collaborate with stakeholders to identify project requirements

• Analyze and document requirements accurately

• Ensure requirements are feasible and align with project goals

• Communicate effectively with team members and stakeholders

DevOps is a software development methodology that combines software development (Dev) with IT operations (Ops) to shorten the systems development life cycle.

• DevOps focuses on collaboration, automation, and integration between developers and IT operations teams.

• It aims to improve the speed and quality of software delivery by breaking down silos and promoting continuous delivery.

• Tools commonly used in DevOps include Jenkins, Docker, Ansible, and Kubernetes.

• DevOps practices incl...read more

Singleton design pattern ensures a class has only one instance and provides a global point of access to it.

• Ensures a class has only one instance by providing a global access point to it

• Uses a private constructor to restrict instantiation of the class

• Provides a static method to access the single instance

• Commonly used in scenarios where only one instance of a class is needed, such as database connections or configuration settings

My name is John Smith.

• My first name is John

• My last name is Smith