Indifi Technologies Software Engineer Interview Questions and Answers

Ajax calls allow for asynchronous communication between client and server without reloading the page.

• Ajax stands for Asynchronous JavaScript and XML

• Uses XMLHttpRequest object to send and receive data

• Allows for partial page updates without reloading the entire page

• Can handle data in various formats such as JSON, XML, HTML, and plain text

• Example: $.ajax({url: 'example.com', success: function(data){console.log(data)}});

REST is lightweight and uses HTTP while SOAP is XML-based and has more features.

• REST uses HTTP methods like GET, POST, PUT, DELETE while SOAP uses XML messaging.

• REST is stateless while SOAP can maintain state.

• REST is faster and easier to use while SOAP is more secure and reliable.

• REST is used for web services while SOAP is used for enterprise-level services.

• Example of REST: Twitter API. Example of SOAP: Amazon Web Serv

GET and POST are HTTP methods used for sending data to a server.

• GET is used to retrieve data from a server

• POST is used to submit data to a server

• GET requests can be cached and bookmarked

• POST requests are not cached and cannot be bookmarked

• GET requests have length restrictions

• POST requests have no length restrictions

• GET requests are less secure than POST requests

Observer pattern is a design pattern in which an object maintains a list of its dependents and notifies them automatically of any state changes.

• Also known as publish-subscribe pattern

• Used in event-driven systems

• Allows loose coupling between objects

• Example: A weather station broadcasts weather updates to multiple displays

• Example: A stock market ticker notifies multiple investors of stock price changes

Singleton is a design pattern that restricts the instantiation of a class to a single object.

• Singleton ensures that only one instance of a class exists in the entire application.

• It provides a global point of access to the instance.

• Commonly used in scenarios where a single instance needs to coordinate actions across the system.

• Example: Database connection manager, logger, configuration manager.

Immutable in Java refers to objects whose state cannot be changed after creation.

• String, Integer, and other wrapper classes are immutable in Java.

• Immutable objects are thread-safe and can be shared without synchronization.

• To create an immutable class, make all fields final and private, and don't provide setters.

• Examples of immutable classes in Java include LocalDate, LocalTime, and LocalDateTime.

Creating immutable in Java

• Use final keyword to make variables immutable

• Use private constructor to prevent object modification

• Use defensive copying to prevent modification of mutable objects

• Use enum to create immutable objects

• Use String class to create immutable strings

Dependency injection is a design pattern that allows objects to receive dependencies rather than creating them internally.

• It helps to decouple the code and makes it more testable and maintainable.

• It allows for easier swapping of dependencies without changing the code.

• There are three types of dependency injection: constructor injection, setter injection, and interface injection.

• Example: Instead of creating a database co...read more

CORS stands for Cross-Origin Resource Sharing. It is a security feature implemented in web browsers to restrict access to resources from different origins.

• CORS allows web servers to specify which origins are allowed to access its resources

• It is implemented using HTTP headers

• CORS prevents malicious websites from accessing sensitive data from other websites

• Examples of resources that may be restricted by CORS include cook

CORS can be overcome by configuring the server to allow cross-origin requests.

• Configure the server to include the Access-Control-Allow-Origin header

• Use JSONP (JSON with Padding) to bypass CORS restrictions

• Use a proxy server to make the request on behalf of the client

• Use a browser extension to disable CORS restrictions during development

• Use a server-side proxy to forward requests to the target server

Implement Binary Search Tree using given array of strings.

• Sort the array in ascending order

• Find the middle element and make it the root of the tree

• Recursively create left and right subtrees using the left and right halves of the array

• Repeat until all elements are added to the tree

Print the given Binary search tree in ascending order

• Traverse the left subtree recursively

• Print the root node

• Traverse the right subtree recursively

Find buy and sell points for maximum profit in an array of stock prices in O(n)

• Iterate through the array and keep track of the minimum price seen so far

• Calculate the profit at each index by subtracting the minimum price from the current price

• Update the maximum profit and buy/sell points accordingly

• Return the buy and sell points for maximum profit

Chennai faces problems related to water scarcity, traffic congestion, and pollution.

• Water scarcity due to inadequate rainfall and poor management of water resources.

• Traffic congestion due to the increasing number of vehicles and poor road infrastructure.

• Pollution caused by industries, vehicular emissions, and improper waste disposal.

Need more context on the question to provide an answer.

• Please provide more information on the problem to be solved.

• Without context, it is difficult to provide a solution.

• Can you please provide more details on the problem statement?

Visa is a global payments technology company that connects consumers, businesses, banks and governments in more than 200 countries and territories.

• Visa operates the world's largest retail electronic payments network.

• VisaNet, the company's global processing system, handles more than 65,000 transaction messages a second.

• Visa is constantly innovating to improve payment security and convenience, with initiatives such as Vi...read more

Autocomplete in IDEs helps developers write code faster by suggesting code snippets and completing code as they type.

• Autocomplete should suggest code snippets based on the context of the code being written

• Autocomplete should prioritize suggestions based on frequency of use

• Autocomplete should also suggest variable and function names

• Autocomplete should be customizable to allow for user-defined snippets and suggestions

• Exa...read more

My weakness is public speaking.

• I tend to get nervous when speaking in front of large groups.

• I am working on improving my public speaking skills by practicing and seeking feedback.

• I have taken courses and attended workshops to help me overcome my fear of public speaking.

Comparing 2 basketball game scenarios with different number of trials and baskets required to win

• Calculate the probability of winning in each game scenario using binomial distribution formula

• Compare the probabilities to determine which game scenario is preferable

• In game1, the probability of winning is p. In game2, the probability of winning is the sum of probabilities of making 2 or 3 baskets

• If p is high, game1 is pref...read more

String manipulation problems involve modifying or analyzing strings of characters.

• Use built-in string methods like substring, replace, and split.

• Regular expressions can be powerful tools for pattern matching and manipulation.

• Be mindful of edge cases like empty strings and null values.

• Consider the time and space complexity of your solution.

• Practice with coding challenges on websites like LeetCode and HackerRank.