P R L Projects & Infrastructure Interview Questions and Answers

Primitive data types are passed by value, while non-primitive data types are passed by reference. Changes in value can occur after downstream operations for non-primitive data types.

• Primitive data types (int, float, char, etc.) are passed by value, meaning a copy of the value is passed to the method. Changes made to the parameter inside the method do not affect the original value.

• Non-primitive data types (objects, arrays, etc.) are passed by reference, meaning the memory addr...read more

Common annotations used in Spring Boot for backend development

• 1. @RestController - used to define a controller and to indicate that the return value of the methods should be directly written to the HTTP response body

• 2. @RequestMapping - used to map web requests to specific handler methods

• 3. @Autowired - used for automatic dependency injection

• 4. @Service - used to indicate that a class is a service

• 5. @Repository - used to indicate that a class is a repository

• 6. @Component - us...read more

The difference between == and .equal() is that == is used to compare values for equality, while .equal() is a method used to compare objects for equality.

• The == operator is used to compare primitive data types like integers, strings, etc. for equality.

• The .equal() method is used to compare objects in Java for equality. It is typically overridden in classes to define custom equality logic.

• Example: int a = 5; int b = 5; System.out.println(a == b); // true

• Example: String str1 = ...read more

Javascript is single threaded.

• Javascript is single threaded, meaning it can only execute one piece of code at a time.

• This is because of the event loop in Javascript, which manages the execution of code.

• Asynchronous operations in Javascript, like setTimeout or AJAX requests, are handled by the event loop.

• Web Workers can be used to achieve multithreading in Javascript for CPU-intensive tasks.

Stream API is a powerful tool in Java for processing collections of objects.

• Advantages include concise code, improved performance, and ease of parallel processing.

• Uses include filtering, mapping, sorting, and reducing data in collections.

• Example: stream.filter(x -> x > 5).map(x -> x * 2).collect(Collectors.toList());

The DB schema of my project includes tables for users, products, orders, and reviews.

• Users table with columns for user ID, username, email, password

• Products table with columns for product ID, name, price, description

• Orders table with columns for order ID, user ID, product ID, quantity

• Reviews table with columns for review ID, product ID, user ID, rating, comment