Welcome back, Sujit Kumar Mishra

Coding Question – Merge Overlapping Time SlotsGiven the following time slots:[(1,3), (2,6), (8,10), (15,18)] Each time slot contains:- First value → Start time- Second value → End timeQuestion:Write a Java program to merge the overlapping time slots and print the final merged intervals. Also, determine how many final merged slots remain after merging.Additionally, explain your complete approach in detail, including:1: The logic used to identify overlapping intervals2: Step-by-step execution flow3: Low-level implementation details4: Time and space complexity of the solution

Microservices CommunicationQuestion:How do two microservices communicate with each other? Please explain the complete process in detail, including common communication patterns and implementation approaches.

Asynchronous Programming in MicroservicesQuestion:Do you have experience with asynchronous programming?How would you implement:1: Synchronous communication2: Asynchronous communicationbetween APIs in a Spring Boot microservices architecture?

Many-to-Many Relationship in Spring JPA/HibernateSuppose there are two entities:· Student· CourseYou need to implement a many-to-many relationship between them.

Exception Handling with @TransactionalQuestion:If an exception occurs inside a method annotated with @Transactional, what type of exception handling behavior will occur?Will the transaction rollback for:1: Checked exceptions?2: Unchecked exceptions?Please explain.

Transaction Management in Spring BootQuestion:Do you have experience with transaction management in Spring Boot?Please explain:1: What is transaction propagation?2: What is transaction isolation?3: What are the different propagation and isolation levels?How are they used with the @Transactional annotation?

JWT – Stateless or StatefulQuestion:Are JWT (JSON Web Tokens) stateless or stateful? Explain the reasoning behind your answer.

Machine Token vs User TokenIn a Spring Boot-based web application:Question:What is the difference between a Machine Token and a User Token? Where and why would each be used?

Securing REST EndpointsYou have developed multiple REST APIs and need to secure them from unauthorized access.Question:How would you secure REST endpoints in a Spring Boot application? Explain the security mechanism and implementation approach.

REST API Rate LimitingYou have developed a REST API endpoint, and you need to restrict it so that no user/client can call the endpoint more than 10 times per second. If someone tries to access the API more than the allowed limit, the request should be blocked.Question:How would you implement this rate-limiting mechanism in a Spring Boot REST API? Explain the approach and technologies/libraries you would use.

Caching & Load Handling - Have you implemented caching in Spring Boot? - How does caching help in handling load and improving performance?

Handling High Load (E-commerce Scenario) - In an e-commerce system, how would you handle situations where many users perform the same action simultaneously? - How would you manage load on both server and database sides?

Service-to-Service Communication- In synchronous communication, how does one microservice call another?

Microservices Communication - Can you explain synchronous vs asynchronous communication between microservices? - When should each approach be used, and how have you implemented them?

Observability & Monitoring - Have you used any observability tools to monitor logs and application performance? - If yes, how did you implement it?

Logging - Which logging framework/mechanism are you currently using in your projects?

Stream API Mapping - In the Stream API, what is the difference between map() and mapToObj()? - When should each be used?

Java 8 Features - What Java 8 features or APIs have you frequently used in your projects?

Exception Handling - How do you handle exceptions in your project? - Can you explain Global Exception Handling in detail?

@Qualifier Annotation - What is the purpose of the @Qualifier annotation in Spring?

Multiple Beans of Same Type - In a configuration class, can you define multiple beans with the same return type (e.g., Employee)? - If yes, how would you differentiate and use them?

Configuration Classes - What is the purpose of a configuration class in Spring Boot? - Why is bean configuration required?

Injecting One Class into Another - If you have two classes, how would you inject one class into another using Spring Boot features?

Dependency Injection - What are the different ways to implement dependency injection in Spring Boot? - Which approach is recommended and why?

Entity vs DTO - What is the difference between an Entity class and a DTO (Data Transfer Object)?

End-to-End Flow- Can you explain the complete end-to-end request flow in a Spring Boot application?- How does a request travel from the client to the database and back, including all intermediate components?

Write a Java program to find the Employee who contributed the maximum transaction amount in the last 30 days.

How you are handling exceptions in your applications globally, not in method level or class level but in application level? 

What kind of interceptors you have used in Spring to intercept the request and response details of a controller endpoint? 

How can I intercept the request coming from frontend UI to certain endpoint and how can I intercept the response of that endpoint which our backend controller is sending to frontend?

How can we avoid possibility of circular dependency using constructor injection approach?

What is circular dependency? 

What is the difference between Serialization or Serializable and Externalization or Externalizable?

How can you create a custom immutable class? 

Can you explain what is immutable class? 

What are the major functions you have used in ReactJS? Can you explain those uses in detail? 

What are the different Hooks you have used in ReactJS? 

In ReactJS, why we used setState() function, why don’t we directly update the state like normal JavaScript? 

What are the advantages of function based components as compared to class based components? 

Difference between function based components and class based components? 

What are the features you have used in ReactJS? 

What is the scope of Bean Injection Problem in Spring? 

What are the different Transaction Propagation Levels in Spring? 

What improvements are required for the Map in Java-8?

What are the different scope of Beans in Spring?

What is composite key in JPA?

What are the ORM frameworks which you have worked on till now? 

What are the databases which you have worked on till now? 

What is package.json file in ReactJS application? What is the use of it exactly? 

Have you ever worked on Authentication and Authorization phase of any application development? Can you explain these processes in detail?

What is the use of API gateways? 

How does one microservice communicate with another microservice?

What is @Qualifier annotation in SpringBoot? 

What are the benefits of using SpringBoot in your project?

What are the difference between ArrayList and HashSet? 

How does HashMap internally works? Explain about this in detail. 

What is the exception handeling in Java and what are the major exceptions related to Java? 

Can you explain about Java-8 features?

What are props in ReactJS? 

What is the difference between function and class in ReactJS? 

What is the difference between undefined and NULL? 

Can you explain the difference between undefined and undeclared variables in JavaScript, when it comes undefined and when it comes undeclared?

What is the callback function in JavaScript? Where did we use this callback function actually? Can we use this callback function from on class to another class in the JavaScript, here class is nothing but different AJAX calls, means can we use callback function for certain AJAX call and the after getting it's response, can we again use the same callback function for the another AJAX call which we are doing from the success response of the first AJAX call? 

Can you tell me some built-in methods in JavaScript? 

What are the different class loaders in JVM? 

What is clustering in Java? 

Java is a single threading programming language or multi threading programming language?

Explain the difference between JDK, JRE and JVM? 

What is a JIT compiler in Java? 

What are the most typical memory leak issues in Java and how do you handle it? 

Do we have a return type for Abstract class and for Interface? 

What is the difference between Abstract class and Interface class in Java? 

How do we configure caching in SpringBoot applications? What are the annotations used for caching? 

How are you handling authentication and authorization in SpringBoot applications?

How can we enable the CrossOrigin resource sharing in SpringBoot? Which builtin method overrides the CrossOrigin resource sharing feature and which annotation mostly we used in this case?

Can you explain the difference between @Component, @Service and @Repository annotations in SpringBoot?