My interview question - java

 🚀 Let's go beyond the basics and explore advanced Stream API operations in Java, including grouping, partitioning, and parallel processing . 1️⃣ Imagine you have a list of employees, and you want to: ✅ Filter employees earning more than $50,000 ✅ Convert employee names to uppercase ✅ Sort employees by salary ✅ Group employees by department ✅ Find the highest-paid employee ✅ Use parallel stream for better performance 📌 Employee Class import java.util.*; import java.util.stream.Collectors; class Employee {     private String name;     private String department;     private double salary;     public Employee(String name, String department, double salary) {         this.name = name;         this.department = department;         this.salary = salary;     }     public String getName() { return name; }     public String getDepartment() { return depa...

1️⃣ What is a Stream in Java?      A Stream in Java (introduced in Java 8 ) is a sequence of data elements that supports functional-style operations like filtering, mapping, and reducing. It helps in processing collections efficiently . Key Features of Streams: ✅ Lazy Evaluation – Operations execute only when needed. ✅ Functional Programming – Uses lambda expressions. ✅ Parallel Processing – Supports parallel execution for better performance. ✅ Immutability – Does not modify the original collection. 2️⃣ How to Create a Stream? 📌  Creating Streams from Collections List<String> names = Arrays.asList("Alice", "Bob", "Charlie"); Stream<String> stream = names.stream(); 📌 Creating Streams from Arrays Stream<String> stream = Stream.of("Apple", "Banana", "Cherry"); 3️⃣ Common Stream Operations 📌 1. Filtering (Filter Elements Based on Condition) List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);...

What is the ResponseEntity in spring boot? ResponseEntity is a powerful and flexible class in Spring Boot that represents the entire HTTP response, including status code, headers, and body. It is part of the Spring Framework's org.springframework.http package and is typically used in RESTful web services built with Spring Boot to provide more control over the HTTP responses sent back to the client. Key Features of ResponseEntity : HTTP Status Code : ResponseEntity allows you to set the HTTP status code of the response, such as 200 OK , 404 Not Found , 500 Internal Server Error , etc. Response Headers : You can set custom HTTP headers in the response. This is useful for sending metadata back to the client, such as content type, authorization tokens, caching information, etc. Response Body : ResponseEntity can also include a response body, which can be any Java object. Spring Boot automatically serializes this object to the appropriate format (like JSON or XML) based on the Cont...