Multi-module maven build : different result from parent and from module

Question

I am migrating an application from ant build to maven 3 build. This app is composed by :

• A parent project specifying all the modules to build
• A project generating classes with jaxb and building a jar with them
• A project building an ejb project
• 3 projects building war modules
• 1 project building an ear

Here is an extract from my parent pom :

<groupId>com.test</groupId>
<artifactId>P</artifactId>
<packaging>pom</packaging>
<version>04.01.00</version>

<modules>
    <module>../PValidationJaxb</module> <-- jar
    <module>../PValidation</module> <-- ejb
    <module>../PImport</module> <-- war
    <module>../PTerminal</module> <-- war
    <module>../PWebService</module> <-- war
    <module>../PEAR</module> <-- ear
</modules>

I have several problems which I think have the same origin, probably a dependency management issue that I cannot figure out :

• The generated modules are different depending on if I build from the parent pom or a single module. Typically if I build PImport only, the generated war is similar to what I had with my ant build and if I build from the parent pom, my war took 20MB, a lot of dependencies from other modules had been added. Both wars are running well.

• My project PWebService has unit tests to be executed during the build. It is using mock-ejb which has cglib as dependency. Having a problem of ClassNotFound with this one, I had to exclude it and add a dependency to cglib-nodep (see last pom extract). If I then build only this module, it is working well. But if I build from the parent project, it fails because other dependencies in other modules also had an implicit dependency on cglib. I had to exclude it in every modules pom and add the dependency to cglib-nodep everywhere to make it run.

Do I miss something important in my configuration ?

The PValidation pom extract :

It is creating a jar containing an ejb with interfaces generated by xdoclet, as well as a client jar.

<parent>
    <groupId>com.test</groupId>
    <artifactId>P</artifactId>
    <version>04.01.00</version>
</parent>
<artifactId>P-validation</artifactId>
<packaging>ejb</packaging>

<dependencies>
    <dependency>
        <groupId>com.test</groupId>
        <artifactId>P-jaxb</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate</artifactId>
        <version>3.2.5.ga</version>
        <exclusions>
            <exclusion>
                <groupId>cglib</groupId>
                <artifactId>cglib</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>cglib</groupId>
        <artifactId>cglib-nodep</artifactId>
        <version>2.2.2</version>
    </dependency>
    ...
    [other libs]
    ...
</dependencies>

<build>
    ...
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-ejb-plugin</artifactId>
            <configuration>
                <ejbVersion>2.0</ejbVersion>
                <generateClient>true</generateClient>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>xdoclet-maven-plugin</artifactId>
            ...

The PImport pom extract :

It depends on both Jaxb generated jar and the ejb client jar.

<parent>
    <groupId>com.test</groupId>
    <artifactId>P</artifactId>
    <version>04.01.00</version>
</parent>
<artifactId>P-import</artifactId>
<packaging>war</packaging>

<dependencies>
    <dependency>
        <groupId>com.test</groupId>
        <artifactId>P-jaxb</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>com.test</groupId>
        <artifactId>P-validation</artifactId>
        <version>${project.version}</version>
        <type>ejb-client</type>
    </dependency>
    ...
    [other libs]
    ...
</dependencies>

The PWebService pom extract :

<parent>
    <groupId>com.test</groupId>
    <artifactId>P</artifactId>
    <version>04.01.00</version>
</parent>

<artifactId>P-webservice</artifactId>
<packaging>war</packaging>

<properties>
    <jersey.version>1.14</jersey.version>
</properties>

<dependencies>
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-servlet</artifactId>
        <version>${jersey.version}</version>
    </dependency>
    <dependency>
        <groupId>com.rte.etso</groupId>
        <artifactId>etso-validation</artifactId>
        <version>${project.version}</version>
        <type>ejb-client</type>
    </dependency>
    ...
    [other libs]
    ...
    <dependency>
        <groupId>org.mockejb</groupId>
        <artifactId>mockejb</artifactId>
        <version>0.6-beta2</version>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>cglib</groupId>
                <artifactId>cglib-full</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>cglib</groupId>
        <artifactId>cglib-nodep</artifactId>
        <version>2.2.2</version>
        <scope>test</scope>
    </dependency>
</dependencies>

Many thanks

Solution after modification of the configuration :

When I got the projects already mavenized, it didnt respect the folder layout convention, but as it was declared in the pom where to find the sources, I thought it would be working. Anyway, i changed it to match the recommended structure.

To build a single module I was executing mvn clean install directly at its level. It is this way I obtained a different result (which is in fact the one I wanted).

Anyway, my problem is solved, I put all the dependencies of the PValidation project as provided, as I am only including the generated client in other modules and they dont require all what is needed for the implementation.

But still I dont get why I had different result for the same configuration.

Answer 1

The first important thing is you should create the structure of your project appropriate to the modules structure which means having the following folder structure:

+-- parent
      +-- PValidationJaxb
      +-- PValidation
      +-- PImport
      +-- PTerminal
      +-- PWebService
      +-- PEAR

This means having a pom.xml which contains the modules definition in the parent folder. if you follow the above recommendation you can simplify the modules list to the following:

<modules>
    <module>PValidationJaxb</module> <-- jar
    <module>PValidation</module> <-- ejb
    <module>PImport</module> <-- war
    <module>PTerminal</module> <-- war
    <module>PWebService</module> <-- war
    <module>PEAR</module> <-- ear
</modules>

Furthermore a best practice in Maven is to use lowercase artifacts which mean in your case pvalidationjaxb instead of PValidationJaxb.

An other important thing is your version which does NOT follow the Maven conventions. Furthermore your version will be from the Maven point of view a release which is not the case you are doing development on this. In Maven you should use a so called SNAPSHOT for such purposes like 1.0.0-SNAPSHOT.

I hope you have followed the folder layout recommendation of Maven which says to put production code (which will be packaged into the resulting jar) into src/main/java whereas test code into src/test/java.

The problem you described having different dependencies sounds weired. The question is how have you tried to build a single moduel? This can usualy be achieved by using the following from the parent location:

mvn -pl module clean package

The problem with your unit tests sounds like a missing dependencies etc. but here is the questions how have you tried to run the unit tests and have you configured maven-surefire-plugin ? Or do you have integration tests? This is only a guess cause i don't see any configuration of Maven plugins in your poms.