Mercedes-Benz Research and Development India Java Technical Lead Interview Questions and Answers

Q1. What are java 8 new features
Ans. 
Java 8 introduced lambda expressions, streams, default methods, and more.
• Lambda expressions for functional programming

• Streams for efficient processing of large data sets

• Default methods to add new functionality to existing interfaces

• Date and Time API for improved handling of date and time

• Optional class to avoid null pointer exceptions

• Nashorn JavaScript engine for improved performance

• Parallel array sorting for faster sor
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Q2. What is the difference between stream and parallel stream
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Stream is sequential while parallel stream is concurrent
• Stream is a sequence of elements that can be processed sequentially

• Parallel stream is a sequence of elements that can be processed concurrently

• Parallel stream can improve performance for large datasets

• Parallel stream uses multiple threads to process elements in parallel

• Stream is suitable for small datasets or when order of processing is important
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Q1. What is one problem that interfaces solve that abstract classes do not?
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Q2. Write a program that takes a string of words, including spaces and special symbols, and returns each occurrence of a specified character, excluding spaces and special symbols.
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Q3. Could you explain how the autowired annotation functions internally?
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Q4. How does Spring Boot determine which data source to use for application execution when multiple data sources are available and no specific profile has been defined?
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Q5. What can you explain about the qualifier annotation?
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It's walkin, so they conducted 1 technical mcqs round.

Q1. Multi threading
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Q2. Internal working of hashmap
Ans. 
HashMap in Java is a data structure that stores key-value pairs and uses hashing to efficiently retrieve values based on keys.
• HashMap uses an array of buckets to store key-value pairs.

• Keys are hashed to determine the index in the array where the key-value pair will be stored.

• In case of hash collisions, a linked list or a balanced tree is used to store multiple key-value pairs in the same bucket.

• HashMap allows null keys...read more
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Q3. Spring batch related
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Q4. Non repeating characters in a array
Ans. 
Function to find and return all non-repeating characters in an array of strings.
• Iterate through the array and count the occurrences of each character using a HashMap.

• Then iterate through the array again and check if the count of each character is 1, if so add it to the result list.

• Return the list of non-repeating characters.
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Q5. 3rd highest salary
Ans. 
To find the 3rd highest salary in a database, we can use a SQL query with the 'LIMIT' and 'OFFSET' keywords.
• Use a SQL query with 'ORDER BY salary DESC' to sort the salaries in descending order.

• Use 'LIMIT 1 OFFSET 2' to skip the first two highest salaries and retrieve the third highest salary.

• Example: SELECT salary FROM employees ORDER BY salary DESC LIMIT 1 OFFSET 2;
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Q6. Qualifier vs primary
Ans. 
A qualifier in Java is used to specify additional information about a primary, which is the main data type or variable.
• A primary in Java is the main data type or variable, while a qualifier provides additional information about the primary.

• Qualifiers can be used to modify the behavior or characteristics of a primary.

• For example, in Java, 'final' is a qualifier that can be used to make a variable constant.
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Q7. Controller vs restcontroller
Ans. 
The main difference is that @RestController is a specialized version of @Controller that is used for RESTful web services.
• Both @Controller and @RestController are used in Spring MVC to handle HTTP requests, but @RestController is specifically used for RESTful web services.

• @Controller is used to create web pages, while @RestController is used to return data in JSON or XML format.

• @RestController is a convenience annotati...read more
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Q8. Spring boot annotataions
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Q9. Oops concepts with examples
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OOP concepts include inheritance, encapsulation, polymorphism, and abstraction.
• Inheritance: Allows a class to inherit properties and behavior from another class. Example: class Dog extends Animal.

• Encapsulation: Bundling data and methods that operate on the data into a single unit. Example: private variables with public getter and setter methods.

• Polymorphism: Ability for objects to be treated as instances of their paren...read more
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Q10. Spring batch configuration
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Q11. They covered all java, spring and Microservices
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Q1. Microservices architecture
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Q2. How do Microservices communicate
Ans. 
Microservices communicate with each other through various communication protocols like HTTP, messaging queues, and gRPC.
• Microservices can communicate over HTTP using RESTful APIs.

• Messaging queues like RabbitMQ or Kafka can be used for asynchronous communication between microservices.

• gRPC is a high-performance, open-source RPC framework that can be used for communication between microservices.

• Service discovery mechanism...read more
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Q3. How to access the Microservice end point
Ans. 
Microservice endpoints can be accessed using HTTP requests with the appropriate URL
• Use HTTP methods like GET, POST, PUT, DELETE to interact with the microservice

• Construct the URL with the base URL of the microservice and the specific endpoint path

• Include any necessary headers or parameters in the request for authentication or data filtering
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Q4. Why we use microservices
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Microservices allow for modular, scalable, and flexible software development by breaking down applications into smaller, independent services.
• Microservices enable easier maintenance and updates as each service can be developed, deployed, and scaled independently.

• They improve fault isolation, as failures in one service do not necessarily affect the entire application.

• Microservices promote agility and faster time-to-mark...read more
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Q1. Tell me about yourself
Ans. 
Experienced Java Developer with a passion for creating efficient and scalable applications.
• Over 5 years of experience in Java development

• Strong knowledge of object-oriented programming principles

• Proficient in Spring framework and Hibernate

• Experience with RESTful web services and microservices architecture

• Familiar with Agile methodologies and version control systems like Git
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Q2. Explain Spring Boot flow in your project
Ans. 
Spring Boot simplifies the development of Java applications by providing a set of tools and conventions.
• Spring Boot eliminates the need for manual configuration by providing defaults and auto-configuration.

• It includes embedded servers like Tomcat, Jetty, or Undertow for easy deployment.

• Spring Boot starters help in quickly setting up dependencies and configurations.

• Annotations like @SpringBootApplication and @RestContro
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Q3. Explain Spring Security flow in your project
Ans. 
Spring Security is used for authentication and authorization in Java projects.
• Spring Security provides authentication and authorization support out of the box.

• It can be configured using XML or Java configuration.

• It supports various authentication mechanisms like form-based, basic, and OAuth.

• Roles and permissions can be defined using annotations or configuration.

• Example: @EnableWebSecurity annotation enables Spring Secu
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Q4. What is @SpringBootApplication
Ans. 
Annotation used to mark a class as a Spring Boot application
• Main annotation in Spring Boot to indicate the starting point of the application

• Combines @Configuration, @EnableAutoConfiguration, and @ComponentScan annotations

• Used to enable the auto-configuration feature in Spring Boot

• Reduces the need for XML configuration in Spring applications
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Q5. Coding Question - Find frequency of all the all the elements in Given String
Ans. 
Find frequency of all elements in a given string
• Create a HashMap to store the frequency of each element in the string

• Iterate through the string and update the frequency in the HashMap

• Convert the HashMap to an array of strings for the final result
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Q1. Introduce yourself
Ans. 
I am a Java Developer with 5 years of experience in developing web applications and implementing software solutions.
• 5 years of experience in Java development

• Proficient in developing web applications

• Skilled in implementing software solutions
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Q2. What is Success according to you
Ans. 
Success is achieving personal goals, feeling fulfilled, and making a positive impact on others.
• Success is subjective and can vary from person to person.

• It is not just about achieving wealth or fame, but also about personal growth and happiness.

• Success can be measured by the impact one has on others and the legacy they leave behind.

• Examples of success include reaching career milestones, maintaining healthy relationships...read more
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Q3. What are your strengths and weekness
Ans. 
My strengths include strong problem-solving skills and attention to detail. My weakness is sometimes being too critical of my own work.
• Strength: Strong problem-solving skills - I enjoy tackling complex problems and finding efficient solutions.

• Strength: Attention to detail - I take pride in producing high-quality work and ensuring accuracy.

• Weakness: Being too critical of my own work - I strive for perfection and sometim...read more
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Q4. Tell me about your Family Background
Ans. 
I come from a close-knit family with a strong emphasis on education and hard work.
• Family is supportive and values education

• Parents are both professionals

• Have a sibling who is also in the tech industry
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Q5. How do you solve any problem
Ans. 
I approach problem-solving by breaking down the issue, researching possible solutions, and testing different approaches.
• Identify the problem and gather all relevant information

• Brainstorm potential solutions and evaluate their feasibility

• Implement the chosen solution and test it to ensure it resolves the problem

• Iterate on the solution if needed to improve its effectiveness
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Q1. I have added the questions below
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Q2. I have added thebelow
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Q1. Based on the resume
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Q1. Scenario based questions
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Q1. Package discussion
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Good coding questions related array and string

Theory plus coding questions

Q1. Core Java , spring boot questions, project
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Q2. Project challenges how resolved
Ans. 
Resolved project challenges through effective problem-solving techniques.
• Identified the root cause of the challenges

• Collaborated with team members to brainstorm solutions

• Implemented appropriate strategies to overcome obstacles

• Tested and validated the implemented solutions

• Documented the resolution process for future reference
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Q3. Difficult situation in project while working with team how resolved
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Q4. Core string concept in depth
Ans. 
Core string concepts include immutability, string manipulation, and string comparison.
• Strings in Java are immutable, meaning they cannot be changed once created.

• String manipulation can be done using various methods like concatenation, substring, and replace.

• String comparison can be done using equals() method for content comparison and == operator for reference comparison.
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Q5. Soft skills questions
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