Short answer
A BOM is a pom-packaged artifact containing only dependencyManagement that declares a tested, mutually-compatible set of versions; you import it with scope=import and type=pom so you get its version declarations without dragging in transitive dependencies.
Explanation
Importing spring-boot-dependencies means you never specify versions for starters, Jackson, Hibernate, and the rest, the BOM pins them, and a single Spring Boot version bump moves dozens of dependencies together to a combination that was actually tested. This eliminates the classic dependency-hell of mismatched library versions and makes upgrades a one-line change with predictable blast radius.
Common mistakes
- Overriding BOM-managed versions without reason.
- Not knowing a BOM is imported with scope import.