Creating multi module Maven Projects in Eclipse - eclipse

Question

Trying to create a multi module maven project in eclipse.
Parent Pom.xml
<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>parent</groupId>
<artifactId>proj1</artifactId>
<version>${myversion}</version>
<packaging>pom</packaging>
<properties>
<myversion>1.0.0</myversion>
</properties>
<modules>
<module>child1</module>
<module>child2</module>
</modules>
</project>
Child-Module 1 Pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>proj1</artifactId>
<groupId>parent</groupId>
<version>${myversion}</version>
</parent>
<groupId>parent</groupId>
<artifactId>child1</artifactId>
<version>${myversion}</version>
</project>
Child Module 2 Pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>proj1</artifactId>
<groupId>parent</groupId>
<version>${myversion}</version>
</parent>
<groupId>parent</groupId>
<artifactId>child2</artifactId>
<version>${myversion}</version>
<dependencies>
<dependency>
<groupId>parent</groupId>
<artifactId>child1</artifactId>
<version>${myversion}</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
</dependencies>
</project>
If I use mvn clean install on command line from the parent folder I can build find. All the projects are build successfully.
But in eclipse I keep getting an error for Child Module 2 pom.xml
Description Resource Path Location Type
parent:child1:1.0.0:jar Missing:
----------
1) parent:proj1:pom:${myversion}
----------
1 required artifact is missing.
for artifact:
parent:proj1:pom:${myversion}
from the specified remote repositories:
central (http://repo1.maven.org/maven2, releases=true, snapshots=false)
pom.xml /child2 line 1 Maven Problem
I need to achieve 2 things
1. have a maven property define the version in the parent pom file.
2. use this property to define the version in all the child modules.
What should I do? I am stuck. Please help.
I am using Eclipse Galileo with m2Eclipse

Answer 1

This can't work, you can't get the version of the parent to use from the parent (and actually, properties don't get substituted in the parent element, see MNG-624). So you need to hard code the version and your parent POM should be:
<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>parent</groupId>
<artifactId>proj1</artifactId>
<version>1.0.0</version>
<packaging>pom</packaging>
<modules>
<module>child1</module>
<module>child2</module>
</modules>
</project>
And in your child POM 1. you need to hardcode the version in /project/parent/version 2. you don't need to specify the <version> (you inherit it) 3. use the ${project.version} property in dependencies.
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>proj1</artifactId>
<groupId>parent</groupId>
<version>1.0.0</version>
</parent>
<groupId>parent</groupId>
<artifactId>child2</artifactId>
<!--version>${myversion}</version--> <!-- Inherited -->
<dependencies>
<dependency>
<groupId>parent</groupId>
<artifactId>child1</artifactId>
<version>${project.version}</version> <!-- use the built-in property here -->
<!--type>jar</type--> <!-- This is a default, you can omit it -->
<!--scope>compile</scope--> <!-- This is a default, you can omit it -->
</dependency>
</dependencies>
</project>
Versionless parent elements will be supported in Maven 3.1.
See also
Missing artifact error in Maven
Eliminate Maven POM Redundancy
Maven 3 - Worth it???