Ant Financial (蚂蚁金服) Interview Question Collection – First, Second, and Third Rounds

First Round (蚂蚁花呗一面) – Questions focus on Java core concepts such as container types (synchronous vs concurrent), time‑complexity of ArrayList and LinkedList, reflection and annotation mechanisms, young generation GC algorithms, HashMap resizing, collision handling, red‑black tree usage, HTTP/HTTPS differences, thread‑pool architecture and blocking‑queue role, Linux load monitoring, Spring MVC request flow, Spring bean wiring, and the rationale behind using AtomicInteger with CAS.

Second Round (蚂蚁花呗二面) – Emphasis shifts to database knowledge: scenarios where indexes are not used, B‑tree implementation of indexes, MySQL master‑slave replication, B+‑tree usage in MySQL, optimistic vs pessimistic locking, experience with NoSQL databases (MongoDB, Redis) and their suitable scenarios, design of distributed TCC transactions, Redis vs Memcache advantages, and capacity planning for Redis data volumes.

Third Round (蚂蚁花呗三面) – Candidates are asked to introduce their projects, discuss architecture and deployment, compare Solr and MongoDB, elaborate on distributed locks and global unique ID generation, identify key metrics for cluster monitoring and optimization, address scaling challenges from millions to billions of records, reflect on recent setbacks and learning, share new technologies studied, and pose questions to the interviewers.

At the end, readers are invited to reply with the keyword “bat” to receive additional BAT interview questions and answers.