Using Maven Reactor for Selective Multi‑Module Builds

The example Maven project uses a parent‑child (aggregator) structure where the top‑level b2b module contains two sub‑modules b2b_account and b2b_order, each of which further contains jar‑type sub‑modules.

Reactor

Running mvn clean install in the b2b/pom.xml directory triggers Maven’s reactor, which analyses inter‑module dependencies and computes a build order for all seven artifacts (including the parent pom). The reactor ensures that modules like b2b-account-api, which are depended on by others, are built first.

Selective Build

When only certain modules need to be rebuilt, Maven provides several options:

-pl <arg>

Alias for --projects <arg>; specifies a comma‑separated list of modules to build. Modules can be referenced by relative path or by groupId:artifactId.

mvn clean install -pl b2b-account
mvn clean install -pl b2b-account/b2b-account-api
mvn clean install -pl b2b-account/b2b-account-api,b2b-account/b2b-account-service
mvn clean install -pl :b2b-account-api,b2b-order/b2b-order-api
mvn clean install -pl :b2b-account-api,:b2b-order-service

-rf <arg>

Alias for --resume-from <arg>; starts the reactor from the specified module, skipping earlier modules.

mvn clean install
mvn clean install -rf b2b-order/b2b-order-service

-amd

Alias for --also-make-dependents; builds the specified modules and any modules that depend on them.

mvn clean install -pl b2b-account/b2b-account-api -amd

-am

Alias for --also-make; builds the specified modules together with all of their dependencies.

mvn clean install -pl b2b-order/b2b-order-service -am

Using these options, developers can efficiently rebuild only the parts of a large e‑commerce project that are affected by changes, avoiding the time‑consuming full build of every module.