Must Know Well:
- Core Java + OOPs (very important)
- Spring Boot (internals, annotations, autoconfiguration)
- Microservices concepts (very high weight)
- Payment Wallet System deep dive (architecture, trade-offs, challenges) 🔗
- Basic REST API design
- Basic SQL / JPA / Hibernate
- Docker basics (why, how you used it)
Should Know Decent:
- LLD + Design Patterns (we'll cover this quickly) 🔗
- Basic DSA (Arrays, Strings, HashMap — 30-40 problems) 🔗
- HLD (high-level only, especially Payment System / Wallet System) 🔗
- Basic AWS concepts (after deployment)
Nice to Have (Lower Priority):
- Advanced Spring Cloud
- Kubernetes basics
- Advanced AWS
- Advanced System Design