Web services are used for communication between applications over a network. In Java backend development, REST and SOAP are two popular approaches for building APIs. Many companies ask REST vs SOAP interview questions to test understanding of API architecture and web service communication. In this article, we will understand the complete difference between REST API … Read more
1. What is Stream API in Java 8? The Stream API is a feature introduced in Java 8 for processing collections of data in a functional and declarative way. It allows developers to perform operations like filtering, mapping, sorting, and collecting data efficiently. Key Features: Example: Output: Real-World Use Case: In e-commerce applications, Stream API … Read more
1. What is Java? Why is it platform independent? Answer: Java is a high-level, object-oriented programming language designed to be platform-independent, meaning you can write code once and run it anywhere. This is possible because Java code is not executed directly by the OS. Instead: Real Example:You build a Spring Boot application on Windows and … Read more
Coding Questions (Must Practice) 1. Find Duplicate Elements in Array Logic: Code: “`java id=”c1″import java.util.*; public class Duplicate {public static void main(String[] args) {int[] arr = {1, 2, 3, 2, 4, 1};Set set = new HashSet<>(); } java id=”c2″public class Largest {public static void main(String[] args) {int[] arr = {10, 20, 5, 40}; } java … Read more
What are Microservices? Answer: Microservices is an architectural style where an application is divided into small, independent services. Each service is responsible for a specific business functionality and can be developed, deployed, and scaled independently. Monolith vs Microservices Monolithic Architecture: Microservices Architecture: Advantages of Microservices Answer: What is API Gateway? Answer: API Gateway acts as … Read more
Coding Questions (Must Practice) 1. Find Duplicate Elements in Array Logic: Code: “`java id=”c1″import java.util.*; public class Duplicate {public static void main(String[] args) {int[] arr = {1, 2, 3, 2, 4, 1};Set set = new HashSet<>(); } java id=”c2″public class Largest {public static void main(String[] args) {int[] arr = {10, 20, 5, 40}; } java … Read more
What is Spring Boot? Answer: Spring Boot is a framework built on top of Spring that simplifies the development of Java applications by reducing configuration and setup time. Key Features: Why use Spring Boot? Answer: Spring Boot is used to quickly build stand-alone and production-ready applications with less boilerplate code. Benefits: What is a REST … Read more
What are OOP Concepts in Java? Object-Oriented Programming (OOP) is a programming paradigm based on the concept of objects, which contain data (variables) and behavior (methods). It helps in writing modular, reusable, and maintainable code. The four main pillars of OOP are: 1. Encapsulation Definition: Encapsulation is the process of wrapping data (variables) and code … Read more
1. Difference between JDK, JRE, and JVM JDK (Java Development Kit) JRE (Java Runtime Environment) JVM (Java Virtual Machine) Flow: Java Code → Compiled by JDK → Bytecode → Executed by JVM (inside JRE) 2. Data Types in Java (Primitive vs Non-Primitive) Primitive Data Types Example: Non-Primitive Data Types Example: 3. String vs StringBuilder vs … Read more
Q1: What is HashMap in Java? Answer: HashMap is a class in the java.util package used to store key-value pairs. Q2: What is ConcurrentHashMap? Answer: ConcurrentHashMap is a thread-safe implementation of Map from java.util.concurrent. Q3: What is the main difference between HashMap and ConcurrentHashMap? Answer: The main difference is thread safety: Q4: Why is HashMap … Read more