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  🟢 30 Basic Java Interview Questions for Freshers (with Examples & Use Cases) If you are preparing for interviews in service-based companies like TCS, Infosys, Accenture, Wipro, Tech Mahindra , these are the most commonly asked Java interview questions for freshers (<1 year experience) . Each question has: ✅ Simple explanation ✅ Real-life use case ✅ Small code example 1. What are the main features of Java? Answer: Object-Oriented Platform Independent Simple, Secure, Robust Multithreaded & Portable 👉 Use Case: Run same .class file on Windows & Linux. public class HelloWorld { public static void main (String[] args) { System.out.println( "Java is platform independent!" ); } } 2. What is JVM, JRE, and JDK? Answer: JVM: Runs Java bytecode. JRE: Libraries + JVM. JDK: JRE + tools (javac, debugger). // javac HelloWorld.java → JDK compiles to bytecode // java HelloWorld → JRE runs program inside JVM 3....

Whether you're a fresh graduate, a data analyst, or a software developer, SQL is one of the most critical skills to master for database-related roles. This guide will walk you through 30 essential SQL interview questions and answers, grouped by difficulty level: Beginner , Intermediate , and Advanced . Beginner SQL Interview Questions with Answers These questions focus on basic SQL syntax, concepts, and simple queries. What is SQL and why is it used? Answer: SQL (Structured Query Language) is used to interact with relational databases. It allows users to query, insert, update, and delete data. What are the different types of SQL statements? Answer: DDL (Data Definition Language): CREATE , ALTER , DROP DML (Data Manipulation Language): SELECT , INSERT , UPDATE , DELETE DCL (Data Control Language): GRANT , REVOKE TCL (Transaction Control Language): COMMIT , ROLLBACK , SAVEPOINT What is the difference between WHERE and HAVING ? Answer: WHERE filters...

  📘 Spring Data JPA Interview Questions (with Answers, Explanations & Use Cases) 1. What is JPA and how is it related to Spring Data JPA? Answer: JPA (Java Persistence API) is a Java specification for managing relational data. Spring Data JPA is a part of Spring Data that simplifies JPA usage by reducing boilerplate code. Use Case: Persisting Java objects (like User ) to a relational database without writing SQL. 2. What are the key annotations used in JPA? Answer: @Entity , @Table , @Id , @GeneratedValue , @Column , @ManyToOne , @OneToMany , etc. Explanation: These annotations map Java objects to database tables and relationships. Use Case: Creating a User entity with an auto-generated ID and fields mapped to table columns. 3. What is the difference between JPA and Hibernate? Answer: JPA is a specification; Hibernate is an implementation of that specification. Use Case: Using Hibernate as the default JPA provider in Spring Boot. 4. How do you define a p...