From Zero to Offers: My Java Backend Interview Journey & Lessons

Self Introduction

The author is a female graduate with a master's from a 985 university and a bachelor's from a 211 university, both in software engineering. She focuses on Java backend development, has no project experience, and began preparing early after seeing peers struggle with job hunting.

Preparation Resources

She studied Java basics through video courses, then frameworks, and read many books such as "剑指 Offer", "大话设计模式", "MySQL 必知必会", "程序员面试金典", "Java 并发编程实战", "计算机操作系统第三版", "计算机网络", "深入理解 Java 虚拟机", "Java 编程思想", "Spring 技术内幕", "Struts2 in Action", and "TCP 详解卷一".

Key Regret

She regrets not practicing LeetCode, which would have helped with problem‑solving skills.

Job Search Strategy

She applied broadly, especially targeting companies in Chengdu, leveraged internal referrals, and attended many interviews to increase chances.

Ant Financial (Internal Referral) – 3 Technical Rounds

HR Round : Very nervous, self‑introduction.

Technical questions: serialization implementation, synchronized implementation, Tomcat cluster synchronization, NoSQL/Redis knowledge, overselling issue in projects, int range.

Second Round : Project overselling solution, data structures, quick sort implementation and complexity, int range details, optimistic vs pessimistic lock, GC, ConcurrentHashMap segment lock details, design pattern categories, concurrency utilities, B‑tree variants, byte vs character differences.

Third Round : Self‑introduction, project overview, server knowledge (JBoss, Apache, WebLogic), backend technologies, Spring IOC advantages, JDK dynamic proxy vs CGLIB, synchronizedMap vs ConcurrentHashMap usage, HTTPS process and encryption, Java thread pool, Redis‑DB consistency, design pattern usage, class loading.

Ctrip (Offer – One Video Interview)

Linked list definition, reversal, cycle detection, balanced binary tree storage, JVM partitioning, JVM GC, maximum subarray sum, final keyword usages, sleep usage, await keyword, thread pool, Spring IOC/AOP advantages, stack and heap definitions.

Meituan Chengdu (Early Batch – Offer)

Paper‑based test covering browser URL access process, DNS lookup, TCP three‑way handshake and four‑way termination, thread pool, design patterns (excluding singleton).

Coding questions: binary search, tree inorder traversal.

Logic puzzle: 5L and 3L bucket to obtain 4L.

ZTE (First Round – Rejected)

Self‑introduction, multithreading code writing, generating non‑repeating three‑digit numbers, SQL index knowledge, table creation, basic Linux commands, willingness to stay in R&D.

Didi (Second Round – Rejected, On‑site)

First round: Hand‑written code to check if s3 can be formed by interleaving s1 and s2 (initial brute force, later DP), hashCode vs equals, implementing a class for HashSet, singleton patterns (enum, double‑checked locking).

Second round: Project discussion, client‑server short‑connection load, code optimization.

Recruit Network (Offer – On‑site)

Self‑introduction, project discussion, Log4j usage, consistent hashing, hobbies, code error reduction, class method declarations, memorable bugs.

Huawei (Offer – On‑site)

Self‑introduction, linked list implementation, project deep dive with architecture diagram, producer‑consumer using blocking queue, suggestion to switch to testing.

Second round: Self‑introduction, programming practice frequency, city preference, personal weaknesses, major project difficulties, team collaboration, questions.

Beibei.com

First round: Self‑introduction, Java synchronization mechanisms, equals vs hashCode, process vs thread, equals vs ==, rectangle stacking problem, detailed browser URL to page process.

Second round: Self‑introduction, deep project questions, repeat of first‑round question 6, process vs thread, learning methods, SQL writing.

HR round: Relocation willingness, other company interests, weekend activities, additional questions.

DJI (Three Rounds)

Self‑introduction, project discussion, family background, motivation to join DJI, handling lack of tasks, personal setbacks, DJI knowledge, questions.

Conclusion

The author emphasizes lifelong learning, improving learning efficiency, and maintaining a growth mindset to stay competitive in the tech industry.