<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>com</groupId>
    <artifactId>a</artifactId>
    <version>${revision}</version>
    <packaging>pom</packaging>

    <properties>
        <vv>2.0</vv>
        <revision>${vv}</revision>
    </properties>

</project>