🔴 1. Data Access & Connection Management These are critical because they affect performance, scalability, and outages. 🔹 Redis ❌ Jedis (older pattern, topology issues) ✅ Lettuce (reactive, auto-reconnect) ✅ Valkey Glide (AWS recommended) 🔹 JDBC Connection Pool ❌ Apache DBCP ❌ C3P0 ✅ HikariCP (default in Spring Boot, fastest, stable) 🔹 ORM / Persistence ❌ Old Hibernate 4.x ❌ MyBatis legacy configs ✅ Hibernate 6+ ✅ Spring Data JPA latest