IBM Java Interview Questions for 3-8 Years Experience | Top 20 Q&A with Code | 2026

🚀 TOP 20 IBM Java Interview Questions & Answers for 3–8 Years Experienced
Developers | Full Code Examples | Spring Boot | Microservices | Java 21

Are you preparing for an IBM Java Developer interview? In this video, I cover
the TOP 20 most asked IBM Java interview questions for developers with 3 to 8
years of experience — with full working code examples you can run directly in
IntelliJ IDEA.

These questions are based on REAL IBM interview experiences shared on Glassdoor,
GeeksForGeeks, and IBM campus drives from 2024–2025. Whether you are targeting
IBM India, IBM GBS, IBM Consulting, or IBM Software — this video covers exactly
what IBM interviewers ask.

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📌 TOPICS COVERED IN THIS VIDEO
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✅ Core Java Internals — HashMap, String Pool, Streams, Optional
✅ Multithreading — Deadlock, ConcurrentHashMap, CompletableFuture
✅ Spring Boot — Auto-Configuration, Bean Scopes, Global Exception Handling
✅ Hibernate & JPA — N+1 Problem and how to fix it
✅ Microservices — Circuit Breaker with Resilience4j, JWT Security
✅ Apache Kafka — Producer, Consumer, Dead Letter Topic
✅ Design Patterns — Thread-safe Singleton (3 approaches)
✅ Modern Java — Virtual Threads (Java 21), Sealed Classes (Java 17)
✅ Architecture — Saga Pattern (Choreography vs Orchestration)
✅ JVM Internals — G1GC vs ZGC, Garbage Collection Tuning

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⏱️ TIMESTAMPS
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00:00 - About This Video
01:11 - What Dip Developer Channel Does
01:28 - Q1: How does HashMap work internally? Hash collision explained
02:53 - Q2: Why is String immutable in Java? What is the String Pool?
03:38 - Q3: Explain deadlock in Java and how to prevent it
04:40 - Q4: Java 8 Stream API — map() vs flatMap() difference
05:53 - Q5: How does Spring Boot Auto-Configuration work internally?
07:05 - Q6: Spring Bean Scopes — Singleton vs Prototype with example
07:55 - Q7: Hibernate N+1 problem — what it is and 3 ways to fix it
08:55 - Q8: Circuit Breaker pattern with Resilience4j in Spring Boot
09:31 - Q9: JWT-based authentication implementation in Spring Boot
10:14 - Q10: CompletableFuture in Java 8 vs Future — key differences
10:58 - Q11: ConcurrentHashMap vs HashMap vs Hashtable
11:18 - Q12: Thread-safe Singleton — all 3 approaches explained
12:12 - Q13: Java 8 Optional — best practices and anti-patterns
12:45 - Q14: Virtual Threads in Java 21 — Project Loom explained
13:50 - Q15: Functional Interfaces in Java 8 — write a custom one
14:39 - Q16: Sealed Classes in Java 17 — real-world example
15:06 - Q17: Apache Kafka integration with Spring Boot
15:40 - Q18: Global Exception Handling in Spring Boot
16:14 - Q19: JVM Garbage Collection — G1GC vs ZGC explained
16:52 - Q20: Saga Pattern — Choreography vs Orchestration
17:07 - Conclusion & What's Next

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📂 FREE GITHUB REPO — All 20 Code Examples
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⭐ Star the repo and download all 20 IntelliJ-ready Java files for free:
👉 https://github.com/TheDipDeveloper/ibm-java-interview-questions

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💬 COMMENT BELOW
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📄 Want the complete read-aloud answer script for all 20 questions?
Comment "SCRIPT" below — I'll share it FREE!

🏢 Which company's Java interview are YOU preparing for?
Drop the company name below — most requested = next video!

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🔔 ABOUT DIP DEVELOPER
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Java interview question videos every week — covering IBM, Infosys, TCS, Wipro,
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Видео IBM Java Interview Questions for 3-8 Years Experience | Top 20 Q&A with Code | 2026 канала Dip Developer