40+ Embicon Tech Hub Interview Questions and Answers

Sample interview questions for Software Engineer position

• Spring vs Spring Boot

• Singleton class in Java

• Marker interface

• Concurrent Hash Map

• Performance issues in SQL/Oracle

• Mapping in Hibernate ORM

• Spring Boot application execution

• Difference between PUT and POST methods

• Authentication in Java application

• Controller class structure in notepad

• Scope of Spring bean

• URL structure and parts

• Difference between Java and JavaScript

• Application execution control flow

• Design patterns in Java

Shell scripting for find and replace, adding index to lines, multithreading, hashmap vs hashtable, stack vs queue

• Use sed command for find and replace in shell scripting

• Use awk command to add an index at the beginning of each line in a file

• Multithreading is the ability of a CPU to execute multiple threads concurrently

• Single threaded means only one thread is executed at a time, while multithreaded allows multiple threads to run simultaneously

• HashMap allows null values and keys,...read more

Yes, I have experience with Junit, SQL and NoSQL databases, Kafka, Dockerization, Java 8 features, stream() operations, and shell scripting in Unix.

• I have used Junit for unit testing in Java projects.

• SQL databases are relational databases that use structured query language for data manipulation, while NoSQL databases are non-relational databases that provide flexible schema design and horizontal scalability.

• I have worked with Kafka for real-time data streaming and processing....read more

The most complex SQL query involved nested queries for data manipulation. Used inner join. Implemented hashset and avoided trees due to their drawbacks.

• Nested SQL query used for complex data manipulation

• Inner join used for combining data from multiple tables

• Implemented hashset for efficient data storage and retrieval

• Avoided trees due to their drawbacks such as unbalanced structure and slower traversal times

Interview questions for Software Engineer position

• GDP is not relevant to the Software Engineer position

• Java 8 features include lambda expressions, streams, and default methods

• Java code snippet: use a HashMap to count occurrences of each number

• Functional programming code: use forEach or map method to iterate over list

OAuth2 is a protocol for authentication and authorization that allows third-party applications to access user data without sharing passwords.

• OAuth2 provides a secure and standardized way for users to grant access to their resources to third-party applications.

• It involves the exchange of tokens between the user, the third-party application, and the resource server.

• Authentication is handled by the authorization server, which verifies the user's identity and issues an access tok...read more

Design patterns in Java are reusable solutions to common software design problems.

• Design patterns should be used when there is a recurring problem in software design.

• Design patterns can improve code readability, maintainability, and scalability.

• Examples of design patterns include Singleton, Factory, Observer, and Decorator.

• It's important to choose the right design pattern for the specific problem at hand.

• Design patterns should not be overused and should be balanced with simpl...read more

Iterate through each character in the array of strings and keep track of the frequency of each character. Return the character with the maximum frequency.

• Create a dictionary to store the frequency of each character

• Iterate through each string in the array and then through each character in the string

• Update the frequency count of each character in the dictionary

• Return the character with the maximum frequency

JWT is a token format while OAuth2 is a protocol. Both can be used to secure REST endpoints.

• JWT is a self-contained token that contains user information and can be used for authentication and authorization.

• OAuth2 is a protocol that allows third-party applications to access user data without sharing passwords.

• To secure REST endpoints, both JWT and OAuth2 can be used depending on the use case.

• For example, JWT can be used for stateless authentication while OAuth2 can be used for...read more

Java 8 streams are functional programming constructs that allow for efficient processing of large data sets.

• Streams are composed of a source, intermediate operations, and a terminal operation.

• Intermediate operations include filter, map, and sorted, and are lazily evaluated.

• Terminal operations trigger the evaluation of the stream and include forEach, reduce, and collect.

• Streams can be parallelized for even greater performance.

• Streams are designed to work with lambdas and funct...read more

Decisions in current project are made through team collaboration and considering project requirements. App architecture is decided based on scalability, performance, and maintainability.

• Decisions are made through team collaboration and discussions

• Consideration of project requirements and goals

• App architecture is decided based on scalability, performance, and maintainability

• Use of design patterns and best practices to guide architecture decisions

Async in Spring Boot allows non-blocking I/O operations, improving application performance.

• Async enables parallel processing of requests, improving throughput.

• It allows the application to handle more requests with the same resources.

• It reduces the response time for long-running operations.

• Use @Async annotation to mark methods as asynchronous.

• Use CompletableFuture to handle async results.

• Example: @Async public CompletableFuture asyncMethod()

• Example: CompletableFuture result = ...read more

Join two tables on a key column using SQL

• Use the JOIN keyword followed by the name of the second table

• Specify the key column in both tables using the ON keyword

• Choose the type of join (INNER, LEFT, RIGHT, FULL) based on your requirement

Fixed thread pool has a fixed number of threads while cached thread pool creates new threads as needed.

• Fixed thread pool is suitable for tasks with a known number of threads

• Cached thread pool is suitable for tasks with unknown number of threads

• Fixed thread pool can cause resource wastage if the number of threads is too high

• Cached thread pool can cause performance issues if the number of threads is too high

• Example: Fixed thread pool can be used for a web server with a fixed nu...read more

The person should commit the changes to the database and refresh the view for others to see.

• Commit the changes to the database

• Refresh the view for others to see

• Ensure proper permissions are set for others to access the data

Using cache with Spring Boot

• Add @EnableCaching annotation to main class

• Add @Cacheable annotation to methods that need caching

• Configure cache properties in application.properties file

• Use CacheManager to manage caches

• Example: @Cacheable(value = "users", key = "#id")

Filter is a method used to extract specific data from a larger set based on certain criteria.

• Filter is required to extract specific data from a larger set.

• It is used to reduce the amount of data that needs to be processed.

• Filter can be applied to arrays, objects, and even strings.

• Examples include filtering out all even numbers from an array or all emails from a list that contain a specific keyword.

Spring app config can be handled using various methods such as XML configuration, Java configuration, and annotation-based configuration.

• XML configuration involves creating an XML file and defining beans and their dependencies.

• Java configuration involves creating a Java class and using annotations to define beans and their dependencies.

• Annotation-based configuration involves using annotations to define beans and their dependencies.

• Spring Boot provides a convenient way to hand...read more

Spring MVC follows the Model-View-Controller (MVC) pattern for building web applications.

• Model represents the data and business logic

• View renders the model data and provides user interface

• Controller handles user requests, updates model and selects view

• Spring MVC provides DispatcherServlet as front controller

• RequestMapping annotation maps URL to controller method

• ModelAndView object returns model data and view name

Improving application performance requires optimizing code, database queries, and server resources.

• Identify and fix slow database queries

• Use caching to reduce server load

• Optimize code by reducing unnecessary loops and improving algorithms

• Use a content delivery network (CDN) to reduce server load

• Upgrade server hardware or use cloud-based resources

• Minimize HTTP requests and reduce file sizes for faster page load times

Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones.

• Declare variables for first two numbers of the series

• Use a loop to generate the series by adding the previous two numbers

• Store the series in an array or print each number as it is generated

Answers to technical questions for Lead Software Engineer position

• Protractor is an end-to-end testing framework for AngularJS applications

• Package lock file is used to lock the version of dependencies installed in a project

• === checks for both value and type equality while == checks for value equality only

• function reverseNumber(num) { return parseInt(num.toString().split('').reverse().join('')) }

Microservices use various communication patterns like synchronous, asynchronous, event-driven, and message-based.

• Synchronous communication involves direct request-response interactions between services.

• Asynchronous communication uses messaging systems like RabbitMQ or Kafka to decouple services.

• Event-driven communication involves services publishing events to a message broker, which other services can subscribe to.

• Message-based communication uses a shared message broker to se...read more

Program to swap two numbers without using temp and encapsulation in Java with example

• Use XOR operator to swap two numbers without using temp variable

• Encapsulation is a mechanism to hide data and methods from outside world

• Example: private variables with public getter and setter methods

Factory facade design patterns are used to provide a simplified interface to a complex system of classes.

• Facade pattern provides a unified interface to a set of interfaces in a subsystem.

• It hides the complexities of the system and provides an easy-to-use interface.

• Examples include Java's JDBC API, which provides a simplified interface to interact with databases.

• Another example is the jQuery library, which provides a simplified interface to manipulate HTML and CSS.

• The Facade p...read more

DFC analysis involves identifying and evaluating the direct and indirect costs associated with a project or decision.

• Identify all direct costs, which are expenses that can be directly attributed to the project or decision.

• Identify all indirect costs, which are expenses that are not directly tied to the project but still impact its overall cost.

• Calculate the total cost by adding up all direct and indirect costs.

• Analyze the cost structure to understand where the majority of cos...read more

My investment philosophy is to focus on long-term growth and value investing.

• I believe in conducting thorough research before making any investment decisions.

• I prioritize companies with strong fundamentals and a competitive advantage in their industry.

• I aim to build a diversified portfolio to mitigate risk and maximize returns.

• I follow a disciplined approach and avoid emotional decision-making.

• I believe in staying informed about market trends and economic indicators.

• Example: ...read more

A star program can be written using nested for loops in any programming language.

• Use two nested for loops to print the rows and columns of the star pattern.

• The number of rows and columns can be determined by the user input or a constant value.

• The star pattern can be created using asterisks or any other character.

• The number of for loops required depends on the complexity of the star pattern.

• For a simple star pattern, only one for loop may be required.

Transactions in microservices are managed using distributed transactions or compensating transactions.

• Distributed transactions involve multiple microservices coordinating with a transaction manager to ensure data consistency across services.

• Compensating transactions involve each microservice having a compensating action to rollback changes if a transaction fails.

• Saga pattern is commonly used in microservices to manage long-running transactions by breaking them into smaller, i...read more

Model attributes play a crucial role in determining the performance of a model.

• Model attributes include features, hyperparameters, and algorithms.

• The choice of attributes can impact the accuracy, speed, and interpretability of the model.

• For example, increasing the number of features can improve accuracy but also increase the risk of overfitting.

• Similarly, adjusting hyperparameters like learning rate can affect the speed and convergence of the model.

• Choosing the right algorith...read more

My favorite subject in DB, DBMS, OS, DS, and OOPs is Database Management Systems (DBMS).

• DB - Database Management Systems are essential for storing, managing, and retrieving data efficiently.

• DBMS - Understanding database concepts like normalization, indexing, and query optimization is crucial for efficient data management.

• OS - Operating Systems play a vital role in managing hardware resources and providing a platform for running applications.

• DS - Data Structures are fundamenta...read more

Machine Learning is a branch of artificial intelligence that involves developing algorithms and models that allow computers to learn from and make predictions or decisions based on data.

• Machine Learning involves training algorithms to learn patterns from data and make predictions or decisions without being explicitly programmed.

• It is used in various applications such as recommendation systems, image recognition, natural language processing, and autonomous vehicles.

• Examples of...read more

Commit command is used to permanently save changes made in a transaction in SQL.

• Commit command is used to end a transaction and make all changes permanent.

• It is used to save changes made in a transaction to the database.

• If a transaction is not committed, the changes made will be rolled back.

• Syntax: COMMIT;

Expectations from Fidelity Investments

• I expect Fidelity Investments to provide a user-friendly platform for managing investments

• I expect timely and accurate updates on my portfolio performance

• I expect a wide range of investment options to choose from

• I expect excellent customer service and support

• I expect competitive fees and expenses

• I expect Fidelity Investments to prioritize security and privacy of my personal and financial information

Angular pipes are used to transform data in templates before displaying it to the user.

• Angular pipes are used in templates to format data before displaying it.

• Pipes can be used to transform strings, numbers, dates, and other types of data.

• There are built-in pipes like 'uppercase', 'lowercase', 'currency', 'date', etc.

• Custom pipes can also be created to suit specific formatting needs.

• Pipes can be chained together to apply multiple transformations to the data.

OAuth is an open standard for authorization that allows users to share their private resources stored on one site with another site.

• OAuth allows users to grant access to their private resources on one site to another site without sharing their credentials.

• It is commonly used by social media platforms to allow users to sign in to third-party apps using their social media accounts.

• OAuth 2.0 is the most widely used version of OAuth and is used by many popular websites and applic...read more

React Js is a JavaScript library for building user interfaces.

• React Js is developed and maintained by Facebook.

• It allows developers to create reusable UI components.

• React uses a virtual DOM for better performance.

• React can be used for building single-page applications.

Highly confident in Java with 8+ years of experience in developing complex applications

• 8+ years of experience in Java development

• Proficient in Java programming language features and best practices

• Extensive experience in developing complex applications using Java

• Familiar with Java frameworks and libraries such as Spring, Hibernate, and Apache Commons

• Comfortable with multi-threading, performance optimization, and debugging in Java

B tree is a self-balancing tree data structure used for indexing and searching large datasets efficiently.

• B trees are commonly used in databases and file systems for indexing

• They have a high fanout factor which reduces the height of the tree and improves search performance

• B trees maintain balance by splitting and merging nodes as needed

• Example: In a database, B tree can be used to quickly locate a specific record based on its key

Quick sort is a divide-and-conquer algorithm that sorts an array by selecting a 'pivot' element and partitioning the array around the pivot.

• Select a pivot element from the array

• Partition the array into two sub-arrays: elements less than the pivot and elements greater than the pivot

• Recursively apply quick sort to the sub-arrays

• Combine the sorted sub-arrays to get the final sorted array

Use quicksort algorithm to efficiently sort the array of strings.

• Implement the quicksort algorithm to sort the array in-place.

• Choose a pivot element and partition the array around it.

• Recursively apply quicksort to the sub-arrays on both sides of the pivot.

• Repeat until the array is sorted.

• Consider using a comparison function to handle string sorting.

Use GROUP BY and HAVING clause to find duplicate values in SQL.

• Use GROUP BY clause to group the data based on the column you want to check for duplicates.

• Use HAVING clause to filter out groups that have more than one entry, indicating duplicates.

• Example: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > 1;

Zookeeper is used for managing Kafka cluster and maintaining its metadata.

• Zookeeper stores metadata about Kafka brokers, topics, partitions, and consumer groups.

• It helps in leader election and broker failure detection.

• Kafka clients use Zookeeper to discover the current state of the Kafka cluster.

• Zookeeper also helps in maintaining the offset of messages consumed by a consumer group.