32 Java Interview Questions

Java Interview Questions

Java backend interview questions: JVM, concurrency, Spring, JUC, and more.

Java HashMap Internal Implementation Explained JVM Garbage Collection Mechanisms Explained Spring IoC and AOP Principles Explained Java Multithreading and Concurrency Fundamentals Why Is Redis So Fast Despite Being Single-Threaded?Redis Persistence: RDB vs AOF Deep Dive Redis Distributed Lock: SETNX, Redlock, and Redisson Cache Penetration, Breakdown, and Avalanche: Redis Cache Problems Cache and Database Consistency: Cache-Aside vs Write-Through Why MySQL InnoDB Uses B+ Trees for Indexes MySQL Transaction Isolation Levels and MVCC Explained MySQL Deadlocks: How to Diagnose and Prevent MySQL Master-Slave Replication: Async, Semi-Sync, and Replication Lag ConcurrentHashMap Internals: From Segment to CAS + synchronized Spring Bean Lifecycle: From Instantiation to Destruction Kafka Message Delivery Guarantees: At-Least-Once, At-Most-Once, Exactly-Once ThreadLocal Internals and Memory Leaks Explained Spring Boot Auto-Configuration: How @EnableAutoConfiguration Actually Works Spring AOP: JDK Dynamic Proxy vs CGLIB Spring Transaction Propagation: REQUIRED, REQUIRES_NEW, and the Common Pitfalls Java CAS and the ABA Problem Explained AQS (AbstractQueuedSynchronizer): How ReentrantLock Actually Works synchronized Lock Upgrade: Biased, Lightweight, Heavyweight Java volatile: Visibility, Ordering, and Why It's Not Atomic JVM Memory Model: Heap, Stack, Metaspace Explained Java ThreadPoolExecutor: How to Tune the 7 Parameters Java Class Loading and the Parent Delegation Model Distributed Transactions: 2PC, TCC, Saga, Outbox Compared Snowflake ID and Distributed ID Generation Strategies Idempotency Design: Tokens, Unique Keys, State Machines Netty Reactor Model and NIO Fundamentals Elasticsearch Inverted Index: How Full-Text Search Works

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