Example project build configuration.

bar-pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project
  xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>demo</groupId>
  <artifactId>bar</artifactId>
  <name>Bar</name>
  <version>0.0.0</version>

  <parent>
    <groupId>demo</groupId>
    <artifactId>root</artifactId>
    <version>0.0.0</version>
  </parent>

  <dependencies>
    <dependency>
      <groupId>demo</groupId>
      <artifactId>foo</artifactId>
      <version>0.0.0</version>
    </dependency>
  </dependencies>
</project>

baz-pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project
  xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>demo</groupId>
  <artifactId>baz</artifactId>
  <name>Baz</name>
  <version>0.0.0</version>

  <parent>
    <groupId>demo</groupId>
    <artifactId>root</artifactId>
    <version>0.0.0</version>
  </parent>

  <dependencies>
    <dependency>
      <groupId>demo</groupId>
      <artifactId>bar</artifactId>
      <version>0.0.0</version>
    </dependency>
  </dependencies>
</project>

foo-pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project
  xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>demo</groupId>
  <artifactId>foo</artifactId>
  <name>Foo</name>
  <version>0.0.0</version>

  <parent>
    <groupId>demo</groupId>
    <artifactId>root</artifactId>
    <version>0.0.0</version>
  </parent>
</project>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project
  xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <packaging>pom</packaging>
  <groupId>demo</groupId>
  <artifactId>root</artifactId>
  <version>0.0.0</version>
  <name>MyProject</name>

  <properties>
    <scala.version>2.10.2</scala.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>${project.build.sourceEncoding}</project.reporting.outputEncoding>
  </properties>

  <modules>
    <module>foo</module>
    <module>bar</module>
    <module>baz</module>
  </modules>

  <dependencies>
    <dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-compiler</artifactId>
      <version>${scala.version}</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>net.alchim31.maven</groupId>
        <artifactId>scala-maven-plugin</artifactId>
        <version>3.1.0</version>
        <configuration>
          <scalaVersion>${scala.version}</scalaVersion>
          <charset>${project.build.sourceEncoding}</charset>
          <jvmArgs>
            <jvmArg>-Xmx1024m</jvmArg>
          </jvmArgs>
          <args>
            <arg>-unchecked</arg>
            <arg>-deprecation</arg>
          </args>
        </configuration>
        <executions>
          <execution>
            <goals>
              <goal>compile</goal>
              <goal>testCompile</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>