Infosys Technology Analyst Interview Questions, Process, and Tips

Exception handling is crucial for any application. Spring Boot provides various ways to handle exceptions globally.

• Spring Boot provides @ControllerAdvice annotation to handle exceptions globally

• Exception handling can be done using @ExceptionHandler annotation

• Spring Boot also provides a default error page for unhandled exceptions

• Custom error pages can be created using ErrorController interface

Configure JPA with Spring Boot

• Add the Spring Data JPA dependency in pom.xml

• Create an entity class with @Entity annotation

• Create a repository interface extending JpaRepository

• Add @EnableJpaRepositories annotation to main class

• Configure database properties in application.properties

• Use @Transactional annotation for database transactions

To communicate between two REST APIs, use HTTP requests and implement security measures such as authentication and encryption.

• Use HTTP requests such as GET, POST, PUT, and DELETE to communicate between two REST APIs

• Implement authentication measures such as OAuth or API keys to ensure secure communication

• Use encryption techniques such as SSL or TLS to protect sensitive data during transmission

• Consider using a message br...read more

Authentication verifies identity, authorization verifies access. Spring Boot uses role-based authorization.

• Authentication confirms the user's identity, authorization determines what the user can access

• Spring Boot uses role-based authorization, where users are assigned roles and permissions are granted to those roles

• Examples of authorization include file permissions, access control lists, and role-based access control

5 Spring boot annotations and their uses

• 1. @SpringBootApplication - used to mark the main class of a Spring Boot application

• 2. @RestController - used to mark a class as a RESTful controller

• 3. @Autowired - used to inject dependencies into a class

• 4. @RequestMapping - used to map HTTP requests to methods in a controller

• 5. @EnableAutoConfiguration - used to enable Spring Boot's auto-configuration feature

Designing a database for a parking lot and creating relationships between tables.

• Create a table for parking spots with a unique ID

• Create a table for vehicles with a unique ID

• Create a table for parking transactions with a unique ID, parking spot ID, and vehicle ID

• Establish a one-to-many relationship between parking spots and parking transactions

• Establish a one-to-many relationship between vehicles and parking transactio

Creating relationships between tables in JPA using entities

• Use annotations such as @ManyToOne, @OneToMany, @OneToOne, and @ManyToMany to define relationships

• Specify the target entity and the mapping column using @JoinColumn

• Use the mappedBy attribute to specify the inverse side of the relationship

• Example: @ManyToOne(targetEntity = Author.class) @JoinColumn(name = "author_id") private Author author;

• Example: @OneToMany(ma

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. Indexing is the process of creating a data structure to improve the speed of data retrieval.

• Normalization involves breaking down a table into smaller tables to reduce redundancy and dependency.

• Indexing involves creating a data structure to improve the speed of data retrieval.

• Normalization and indexing are impo...read more

Primary key uniquely identifies a record in a table, while unique key ensures uniqueness of a column.

• Primary key cannot have null values, while unique key can have one null value.

• A table can have only one primary key, but multiple unique keys.

• Primary key is used as a foreign key in other tables to establish relationships.

• Example: Employee ID can be a primary key, while email can be a unique key in an employee table.

A unique composite key is a combination of two or more columns that uniquely identifies a record in a table.

• It is used to ensure data integrity and avoid duplicate records.

• It is created by combining two or more columns that individually may not be unique.

• Examples include a combination of first name, last name, and date of birth in a patient database.

• It is commonly used in database design and normalization.

Singleton and Factory are design patterns used in software development.

• Singleton pattern ensures that only one instance of a class is created and provides a global point of access to it.

• Factory pattern provides an interface for creating objects in a superclass, but allows subclasses to alter the type of objects that will be created.

• Singleton pattern is useful when we need to limit the number of instances of a class tha...read more

An immutable class is a class whose objects cannot be modified after creation.

• Make all fields private and final

• Do not provide any setter methods

• Ensure that any mutable objects are defensively copied

• Override equals() and hashCode() methods

• Make the class final

A class in Spring MVC that provides global exception handling and model attributes for all controllers.

• Used to handle exceptions across multiple controllers

• Can add common model attributes to all controllers

• Can be used to customize error responses

• Can be annotated with @RestControllerAdvice to return JSON responses

The @primary annotation is used to mark a primary key in a database table.

• It is used in database design to indicate the primary key of a table

• It is often used in conjunction with other annotations such as @Entity and @Id

• It can be used to specify the name of the primary key column

• Example: @Entity @Table(name = "users") public class User { @Id @GeneratedValue @Column(name = "user_id") private Long id; }

Creating a Spring Boot application for web and database operations

• Create a new Spring Boot project using Spring Initializr

• Add necessary dependencies for web and database operations in pom.xml

• Create a database schema and configure database connection in application.properties

• Create entity classes and corresponding repositories

• Create REST controllers for web operations

• Test the application using Postman or any other REST

To write a REST API for updating and creating a new resource, follow these pointers.

• Define the API endpoint and HTTP method for creating and updating resources

• Validate the input data and handle errors appropriately

• Update or create the resource in the database

• Return a response with the updated or created resource and a status code indicating success

Oops concepts are the fundamental concepts of object-oriented programming.

• Encapsulation - binding data and functions together

• Inheritance - creating new classes from existing ones

• Polymorphism - ability of objects to take on multiple forms

• Abstraction - hiding implementation details from users

Interface and abstract are both used for abstraction in object-oriented programming.

• Interfaces define a contract that a class must implement.

• Abstract classes provide a base implementation that can be extended by subclasses.

• Interfaces can be implemented by multiple classes, while a class can only extend one abstract class.

• Interfaces can only have abstract methods, while abstract classes can have both abstract and concre

ArrayList is non-synchronized and Vector is synchronized.

• ArrayList is faster than Vector.

• Vector is thread-safe while ArrayList is not.

• Vector is a legacy class while ArrayList is not.

• Vector doubles its size while ArrayList increases by 50%.

• ArrayList is preferred over Vector in most cases.