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Shop101 Interview Questions and Answers
Q1. How interface is implemented in java
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 all methods defined in the interface.
Interfaces can also c...read more
Q2. Difference between arraylist and linked list
ArrayList is resizable array implementation, LinkedList is doubly linked list implementation.
ArrayList uses dynamic array to store elements, LinkedList uses doubly linked list.
ArrayList is faster for accessing elements by index, LinkedList is faster for adding/removing elements.
Example: ArrayList
arrList = new ArrayList<>(); LinkedList linkedList = new LinkedList<>();
Q3. Difference between throw and throwable
throw is a keyword used to explicitly throw an exception, while Throwable is a class that serves as the base class for all exceptions in Java.
throw is used to throw an exception in a method, while Throwable is the superclass of all exceptions in Java.
throw is followed by an instance of Throwable class or its subclasses, while Throwable is a class that provides common methods for handling exceptions.
Example: throw new NullPointerException(); - throws a NullPointerException
Exam...read more
Q4. Benefits of springboot over spring
Spring Boot simplifies the setup and development of Spring applications by providing a convention-over-configuration approach.
Spring Boot eliminates the need for XML configuration by using annotations and sensible defaults.
It includes embedded servers like Tomcat, Jetty, or Undertow, making it easy to deploy standalone applications.
Auto-configuration feature reduces the amount of boilerplate code needed to set up a Spring application.
Actuator module provides production-ready ...read more
Q5. How REST API used
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 APIs typically return data in JSON or XML format.
Authentica...read more
Q6. How stream API works
Stream API in Java provides a way to process collections of objects in a functional style.
Stream API allows for functional-style operations on collections like map, filter, reduce, etc.
It supports lazy evaluation, meaning operations are only performed when needed.
Streams can be sequential or parallel, depending on the source and operations used.
Q7. Transactions in springboot
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 database operations within that method are part of a single tran...read more
Q8. Annotations in springboot
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.
Q9. Features of java 8
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 allow for adding new methods to interfaces without breakin...read more
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