UST Senior Software Developer Interview Questions, Process, and Tips

Round duration - 60 minutes
Round difficulty - Medium

This round had 1 question related to DSA and then the rest of the questions were from Java , OOPS and Spring Boot.

Q1. Find the middle of a given linked list
Given the head node of the singly linked list, return a pointer pointing to the middle of the linked list.
If there are an odd number of elements, return the middle...read more
Ans. 
Approach :

1) If the head is NULL, we simply return HEAD.

2) If there is only one element in the linked list, we simply return it as it is the midpoint.

3) Otherwise, we initialise 2 pointers ‘fast’ and ‘slow’ both poiniting to head initially.

4) We traverse the linked list until fast is the last element or fast is beyond the linked list i.e it points to NULL.

5) In each iteration, the ‘fast’ pointer jumps 2 times faster as...read more
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Q2. Java Question
How ConcurrentHashMap works in Java?
Ans. 
According to ConcurrentHashMap Oracle docs,

The constructor of ConcurrentHashMap looks like this :

public ConcurrentHashMap (int initialCapacity, float loadFactor, int concurrencyLevel)

So the above line creates a new, empty map with the specified initial capacity, load factor and concurrency level where, Important Parameters to consider from ConcurrentHashMap Constructor :

initialCapacity - the initial capacity. The imple...read more
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Q3. Java 8 Question
What are the features of a lambda expression?
Ans. 
Below are the two significant features of the methods that are defined as the lambda expressions :

1) Lambda expressions can be passed as a parameter to another method.
 
2) Lambda expressions can be standalone without belonging to any class.
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Q4. Spring Boot Question
What is dependency Injection?
Ans. 
The process of injecting dependent bean objects into target bean objects is called dependency injection.

1) Setter Injection : The IOC container will inject the dependent bean object into the target bean object by calling the setter method.

2) Constructor Injection : The IOC container will inject the dependent bean object into the target bean object by calling the target bean constructor.

3) Field Injection : The IOC cont...read more
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Q5. API Question
Difference between PUT and POST methods?
Ans. 
1) PUT method is called when you have to modify a single resource while POST method is called when you have to add a child resource.

2) PUT method response can be cached but you cannot cache POST method responses.

3) You can use UPDATE query in PUT whereas you can use create query in POST.

4) In PUT method, the client decides which URI resource should have, and in POST method, the server decides which URI resource should ...read more
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Q6. OOPS Question
Explain SOLID principles in Object Oriented Design.
Ans. 
The SOLID principle is an acronym of the five principles which is given below :

1) Single Responsibility Principle (SRP)
2) Open/Closed Principle
3) Liskov’s Substitution Principle (LSP)
4) Interface Segregation Principle (ISP)
5) Dependency Inversion Principle (DIP)

Uses of SOLID design principles :

1) The SOLID principle helps in reducing tight coupling.

2) Tight coupling means a group of classes are highly dependent on one ...read more
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Q7. OOPS Question
What do you mean by virtual functions in C++?
Ans. 
1) A C++ virtual function is a member function in the base class that you redefine in a derived class. It is declared using the virtual keyword.

2) It is used to tell the compiler to perform dynamic linkage or late binding on the function.

3) When the function is made virtual, C++ determines which function is to be invoked at the runtime based on the type of the object pointed by the base class pointer.

Some rules regardi...read more
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Round duration - 60 minutes
Round difficulty - Medium

This round started with some questions from Spring Boot and Hibernate and then the interviewer moved on to some more questions from MVC and Microservices.

Q1. Spring Boot Question
What Are the Basic Annotations that Spring Boot Offers?
Ans. 
The primary annotations that Spring Boot offers reside in its "org.springframework.boot.autoconfigure" and its sub-packages. Here are a couple of basic ones :

@EnableAutoConfiguration – to make Spring Boot look for auto-configuration beans on its classpath and automatically apply them.

@SpringBootApplication – used to denote the main class of a Boot Application. This annotation combines @Configuration, @EnableAutoConfigu...read more
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Q2. Spring Boot Question
Explain @RestController annotation in Sprint boot?
Ans. 
It is a combination of @Controller and @ResponseBody, used for creating a restful controller. It converts the response to JSON or XML. It ensures that data returned by each method will be written straight into the response body instead of returning a template.
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Q3. Hibernate Question
What is hibernate caching?
Ans. 
Hibernate caching is the strategy for improving the application performance by pooling objects in the cache so that the queries are executed faster. Hibernate caching is particularly useful when fetching the same data that is executed multiple times. Rather than hitting the database, we can just access the data from the cache. This results in reduced throughput time of the application. 

Types of Hibernate Caching

Fi...read more
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Q4. Hibernate Question
Can you tell something about the N+1 SELECT problem in Hibernate?
Ans. 
N+1 SELECT problem is due to the result of using lazy loading and on-demand fetching strategy. Let's take an example. If you have an N items list and each item from the list has a dependency on a collection of another object, say bid. In order to find the highest bid for each item while using the lazy loading strategy, hibernate has to first fire 1 query to load all items and then subsequently fire N queries to load bi...read more
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Q5. Hibernate Question
What are the concurrency strategies available in hibernate?
Ans. 
Concurrency strategies are the mediators responsible for storing and retrieving items from the cache. While enabling second-level cache, it is the responsibility of the developer to provide what strategy is to be implemented to decide for each persistent class and collection.

Following are the concurrency strategies that are used :

1) Transactional: This is used in cases of updating data that most likely causes stale dat...read more
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Q6. MVC Question
Explain in brief the role of different MVC components?
Ans. 
The different MVC components have the following roles -

1) Presentation : This component takes care of the visual representation of a particular abstraction in the application.

2) Control : This component takes care of the consistency and uniformity between the abstraction within the system along with their presentation to the user. It is also responsible for communicating with all other controls within the MVC system.

3)...read more
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Q7. MVC Question
How is the routing carried out in MVC?
Ans. 
1) The RouteCollection contains a set of routes that are responsible for registering the routes in the application.

2) The RegisterRoutes method is used for recording the routes in the collection.

3) The URL patterns are defined by the routes and a handler is used which checks the request matching the pattern.

4) The MVC routing has 3 parameters.
4.1) The first parameter determines the name of the route.
4.2) The second par...read more
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Q8. Microservices Question
Explain how independent microservices communicate with each other.
Ans. 
Communication between microservices can take place through :

1) HTTP/REST with JSON or binary protocol for request-response

2) Websockets for streaming.

3) A broker or server program that uses advanced routing algorithms.

RabbitMQ, Nats, Kafka, etc., can be used as message brokers; each is built to handle a particular message semantic. You can also use Backend as a Service like Space Cloud to automate your entire backend.
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Q9. Microservices Question
Explain OAuth.
Ans. 
Generally speaking, OAuth (Open Authorization Protocol) enables users to authenticate themselves with third-party service providers. With this protocol, you can access client applications on HTTP for third-party providers such as GitHub, Facebook, etc. Using it, you can also share resources on one site with another site without requiring their credentials.
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Round duration - 30 minutes
Round difficulty - Easy

This was a Technical Cum HR round where I was first asked some basic Java related concepts and then we discussed about my expectations from the company , learnings and growth in the forthcomig years. I would suggest be honest and try to communicate your thoughts properly in these type of rounds to maximise your chances of getting selected.

Q1. Basic HR Questions
Why should we hire you ?
What are your expectations from the company?
How was your overall interview experience?
What are your strengths and weakness according to you?
Where do you see yourse...read more
Ans. 
Tip 1 : The cross questioning can go intense some time, think before you speak.

Tip 2 : Be open minded and answer whatever you are thinking, in these rounds I feel it is important to have opinion.

Tip 3 : Context of questions can be switched, pay attention to the details. It is okay to ask questions in these round, like what are the projects currently the company is investing, which team you are mentoring. How all is the
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Q2. Basic HR Question
Why are you looking for a job change?
Ans. 
Tip : For an experienced professional seeking a change, this is a common question. The easiest method to respond to this question is to state that you are leaving your current work in order to advance your career. Make sure you don't criticize or speak poorly about the company where you now work.
Answered by CodingNinjas
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