HCL Group Interview Questions and Answers

Q1. Transactions in springboot
Ans. 
Transactions in Spring Boot manage database operations as a single unit of work to ensure data integrity.
• Spring Boot provides support for declarative transaction management using @Transactional annotation.

• Transactions can be configured at class or method level.

• Transactions can be rolled back in case of exceptions to maintain data consistency.

• Example: @Transactional annotation on a service method ensures that all databa...read more
Answered by AI
Add your answer
Q2. Difference between arraylist and linked list
Add your answer
Q3. How REST API used
Ans. 
REST API is used to communicate between client and server using HTTP methods like GET, POST, PUT, DELETE.
• REST API allows clients to access and manipulate resources on a server using standard HTTP methods.

• It uses URLs to identify resources and HTTP methods to perform actions on those resources.

• Common HTTP methods used in REST API are GET (retrieve data), POST (create data), PUT (update data), DELETE (remove data).

• REST A...read more
Answered by AI
Add your answer
Q4. Annotations in springboot
Ans. 
Annotations in Spring Boot are used to provide metadata about the application and its components.
• Annotations are used to configure Spring Boot applications, define beans, handle requests, etc.

• Examples include @SpringBootApplication, @RestController, @Autowired, @RequestMapping, etc.
Answered by AI
Add your answer
Q5. Features of java 8
Ans. 
Java 8 introduced several new features including lambda expressions, functional interfaces, streams, and default methods in interfaces.
• Lambda expressions allow for more concise code and enable functional programming.

• Functional interfaces are interfaces with a single abstract method, used for lambda expressions.

• Streams provide a way to work with collections of objects in a functional style.

• Default methods in interfaces ...read more
Answered by AI
Add your answer
Q6. How interface is implemented in java
Ans. 
Interfaces in Java are implemented using the 'implements' keyword, allowing classes to provide specific implementations for methods defined in the interface.
• Interfaces in Java define a contract for classes to implement, specifying method signatures without implementations.

• A class can implement multiple interfaces by separating them with commas.

• Classes implementing an interface must provide concrete implementations for ...read more
Answered by AI
Add your answer
Q7. How stream API works
Add your answer
Q8. Benefits of springboot over spring
Add your answer
Q9. Difference between throw and throwable
Add your answer

Q1. Technical and optimization techniques related
Add your answer
Q2. Coding questions of java script
Add your answer

Aptitude test assess the candidate’s cognitive abilities ,skills and potential for learning.

A group discussion is a structured conversation among a group of people usually 6-12 participants , moderated by facilitator.

Q1. Can you tell me about yourself?
Add your answer
Q2. Why do you want to work for company
Add your answer
Q3. What are your greatest strengths and weaknesses?
Add your answer
Q4. How do you handle change or unexpected situations?
Add your answer
Q5. What are your greatest strengths and weaknesses?
Ans. 
My greatest strength is my ability to communicate effectively and empathize with customers. My weakness is that I can be overly detail-oriented at times.
• Strength: Effective communication skills - able to convey information clearly and concisely

• Strength: Empathy towards customers - able to understand their needs and concerns

• Weakness: Being overly detail-oriented - sometimes spend too much time focusing on minor details

• W...read more
Answered by AI
Add your answer
Q6. How do you handle chane or unexpected situations?
Ans. 
I handle change or unexpected situations by staying calm, assessing the situation, and adapting quickly.
• Stay calm and composed

• Assess the situation and understand the impact

• Adapt quickly and come up with a solution

• Communicate effectively with team members or customers
Answered by AI
Add your answer

Q1. How are you, what is your name, where are you from
Ans. 
I am doing well, my name is John Smith, and I am from New York.
• I am doing well

• My name is John Smith

• I am from New York
Answered by AI
Add your answer
Q2. Hola siva India flag
Add your answer
Q3. Siva Reddy vanga india
Add your answer
Q4. India vanga siva reddy
Add your answer
Q5. King movie good only
Add your answer

Q1. NA- rude behaviour by interviewer
Add your answer
Q2. NA
Add your answer

Q1. Data Modelling related questions, SCD,snowflake and star schema
Add your answer
Q2. Join strategy while joining large dataframes- sort -merge join vs broadcast join
Add your answer
Q3. Pyspark code to read csv and cast all columns to string
Ans. 
Use PySpark to read a CSV file and convert all columns to string type for uniformity.
• Import necessary libraries: `from pyspark.sql import SparkSession`.

• Create a Spark session: `spark = SparkSession.builder.appName('CSV Reader').getOrCreate()`.

• Read the CSV file: `df = spark.read.csv('path/to/file.csv', header=True, inferSchema=True)`.

• Cast all columns to string: `df = df.select([col(c).cast('string').alias(c) for c in df...read more
Answered by AI
Add your answer
Q4. Spark optimization techniques. How to handle data skewness?
Ans. 
Optimize Spark jobs by addressing data skewness through partitioning, salting, and using efficient aggregations.
• Use custom partitioning to distribute data evenly across partitions, e.g., using a hash function on the key.

• Implement salting by adding a random prefix to skewed keys to distribute load, e.g., 'key1_1', 'key1_2'.

• Leverage the `reduceByKey` transformation instead of `groupByKey` to minimize data shuffling.

• Consi...read more
Answered by AI
Add your answer
Q5. Iceberg vs Hive.
Ans. 
Iceberg and Hive are data management tools for big data, with distinct features for handling data lakes and analytics.
• Iceberg is an open table format for large analytic datasets, while Hive is a data warehouse software built on top of Hadoop.

• Iceberg supports schema evolution, allowing changes to the table schema without affecting existing data.

• Hive uses a SQL-like language (HiveQL) for querying, making it accessible fo...read more
Answered by AI
Add your answer

Q1. Explain Snowflake Architecture
Ans. 
Snowflake Architecture is a cloud-based data warehousing platform that separates storage and compute for increased scalability and performance.
• Snowflake uses a unique architecture with three layers: storage, compute, and services.

• Data is stored in Amazon S3 or Microsoft Azure Blob Storage, separate from the compute resources.

• Compute resources can be scaled up or down independently of storage, allowing for flexibility a...read more
Answered by AI
Add your answer
Q2. What is Multi-clustering
Ans. 
Multi-clustering is a feature in Snowflake that allows data to be stored in multiple clusters for improved performance and scalability.
• Improves query performance by distributing data across multiple clusters

• Increases scalability by allowing more resources to be added as needed

• Helps in workload isolation and resource management

• Example: Storing customer data in one cluster and product data in another for better performan...read more
Answered by AI
Add your answer
Q3. 2 SQL scenario questions
Add your answer