What is the primary role of a BOM (Bill of Materials) in a multi-module Maven project?

• A. Centralizes version management for plugins and dependencies
• B. Defines packaging types for modules
• C. Specifies the build lifecycle
• D. Holds all source code for modules

Answer: (A)

The main concept here is that a BOM (Bill of Materials) serves to centralize version management for dependencies and plugins across a multi-module Maven project. It’s a POM file that provides a single, authoritative set of versions. Modules in the project typically declare their dependencies without specifying versions; they rely on the BOM’s dependencyManagement (often brought in with an import) to resolve to consistent versions everywhere. This makes upgrades simpler and prevents version conflicts from arising in transitive dependencies.

A BOM doesn’t define packaging types—that’s configured in each module’s POM. It doesn’t specify the build lifecycle, which is governed by Maven’s standard lifecycle. It also doesn’t hold all the source code for modules; it’s purely metadata about which versions to use.