š“ 1. Data Access & Connection Management These are critical because they affect performance, scalability, and outages. š¹ Redis ā Jedis (older pattern, topology issues) ā Lettuce (reactive, auto-reconnect) ā Valkey Glide (AWS recommended) š¹ JDBC Connection Pool ā Apache DBCP ā C3P0 ā HikariCP (default in Spring Boot, fastest, stable) š¹ ORM / Persistence ā Old Hibernate 4.x ā MyBatis legacy configs ā Hibernate 6+ ā Spring Data JPA latest