Java Backend track

Java Backend interview questions

Core Java to Spring Boot. 12 chapters, 2468+ real interview questions with model answers — learn each concept and practise how to answer it. In English & Hinglish.

214+ topics · Free to start

Why this track works

Learn only what Java Backend interviews actually ask.

12 chapters, 60–90 minutes each. Every concept starts with a real-world problem — the kind production code throws at you. No wall of theory, no textbook topics the industry never touches. Learn → test yourself → take an AI mock → fix your weak spots.

  • 📖LearnConcept + real-world problem, 60–90 min
  • 🧠RememberModel answers + flashcards
  • 🤖PractiseAI mock + weak-topic report
Full video coursebuilt around a syllabus40h+
Hirenix trackbuilt around interviews~18h

The difference isn’t the content — it’s the filter. Only what’s actually used in production and actually asked in interviews. Textbook topics the industry never touches don’t make the cut.

Start free🌐 English🇮🇳 Hinglish

Certificates

Finish the Java Backend track. Get certified.

Every Java Backend chapter you complete earns a certificate with your name on it, issued instantly. Finish all 12 chapters and you earn the Java Backend Stack Mastery certificate. No exam, no waiting.

  • Chapter certificate

    One for each of the 12 Java Backend chapters you complete.

  • Stack Mastery certificate

    Complete all 12 chapters for the Java Backend Stack Mastery certificate.

  • Anyone can verify it

    Each certificate has a QR code and a public link at hirenix.in/verify.

Start learning — freeCertificates are included with Pro.
Sample Hirenix Certificate of Completion with the learner's name and a verification QR code

Verified credential

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Core Java

Java

What is Java? JVM, JRE, JDK · Anatomy of a Java program · Data types and variables · Operators and control flow · Strings and the String pool

16 topics · 184 questions

View Core Java questions

Object-Oriented Java

Java

Classes and objects · Constructors · Encapsulation and access modifiers · Inheritance and super · Polymorphism: overloading vs overriding

17 topics · 201 questions

View Object-Oriented Java questions

Collections and Generics

Java

Collections framework overview · List: ArrayList vs LinkedList · Set: HashSet, LinkedHashSet, TreeSet · Map and HashMap basics · How HashMap works internally

18 topics · 211 questions

View Collections and Generics questions

Exceptions and File I/O

Java

Exceptions and the Throwable hierarchy · Checked vs unchecked exceptions · try, catch, finally · throw vs throws, and propagation · Multi-catch and catch order

18 topics · 203 questions

View Exceptions and File I/O questions

Java 8 and Functional Programming

Java

Why Java went functional · Lambda expressions · Functional interfaces and @FunctionalInterface · Predicate, Function, Consumer, Supplier · Method and constructor references

19 topics · 239 questions

View Java 8 and Functional Programming questions

Concurrency

Java

Why Java programs need concurrency · Creating threads: Thread vs Runnable · Thread lifecycle, sleep, join, interrupt · synchronized keyword and explicit Locks · volatile and the Java Memory Model

18 topics · 205 questions

View Concurrency questions

Spring Core & Dependency Injection

Java

Why Spring: IoC and the Dependency Inversion Principle · Dependency injection: constructor vs setter vs field · The IoC container: BeanFactory and ApplicationContext · Bean definitions: XML, Java config, and component scan · Bean scopes: singleton, prototype, and web scopes

18 topics · 205 questions

View Spring Core & Dependency Injection questions

Spring Boot & Auto-configuration

Java

Why Spring Boot: what it adds on top of Spring · How auto-configuration actually works · SpringBootApplication and the base-package trap · Starters, the BOM, and dependency management · Conditional annotations: OnClass, OnMissingBean, OnProperty

18 topics · 206 questions

View Spring Boot & Auto-configuration questions

Spring Data JPA & Hibernate

Java

Why JPA: what ORM solves, and JPA vs Hibernate vs Spring Data · Entities and mapping: Entity, Id, GeneratedValue, Column · The persistence context and EntityManager · Repositories and derived query methods · JPQL, the Query annotation, and native queries

18 topics · 203 questions

View Spring Data JPA & Hibernate questions

Spring Security

Java

Why Spring Security: what you get before you write any config · The security filter chain and its order · Authentication vs authorization: 401 vs 403 · UserDetailsService and authentication providers · Password storage: BCrypt and the encoder prefix

18 topics · 204 questions

View Spring Security questions

Spring Testing

Java

Why test Spring apps: unit, slice and full-context tests · JUnit 5 essentials: lifecycle, assertions and parameterized tests · AssertJ and assertions that explain their own failure · Mockito fundamentals: mock, stub, verify and strict stubs · SpringBootTest and its web environments: MOCK vs RANDOM_PORT

18 topics · 203 questions

View Spring Testing questions

Spring Microservices

Java

Why microservices: what you gain, what you pay, and when a monolith wins · Service-to-service calls: RestClient and HttpExchange interfaces · Timeouts: how one slow service drags down the caller · Retries and idempotency: when a retry creates a duplicate · Circuit breakers with Resilience4j: closed, open and half-open

18 topics · 204 questions

View Spring Microservices questions