Maven EAR Plugin Modules

Question

To build a Java EE application with Maven, one can use the following configuration:

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-ear-plugin</artifactId>
                <version>3.0.2</version>
                <configuration>
                    <modules>
                        <webModule>
                           [..]
                        </webModule>
                        <ejbModule>
                            [..]
                        </ejbModule>
                        <jarModule>
                            [..]
                        </jarModule>
                    </modules>
                </configuration>
            </plugin>

I understand that the web module is packaged differently from other modules, that is, for example, being located at the root of the ear and having packed it's own dependencies to WEB-INF/lib.

But what about jar and ejb modules? How are they different from each other? And what is the difference of defining a jar as a normal dependency and/or defining it as a jarModule or earModule?

Beeing more precise, what is the difference between the following setups:

1. ejb module defined as ejbModule

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-ear-plugin</artifactId>
                <version>3.0.2</version>
                <configuration>
                    <modules>
                        <webModule>
                            [..]
                        </webModule>
                        <ejbModule>
                             <groupId>org.example</groupId>
                             <artifactId>helloworld-model</artifactId>
                            <version>1.0-SNAPSHOT</version>
                        </ejbModule>
                    </modules>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
</build>


<dependencies>
    
</dependencies>

2. ejb module defined as dependency

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-ear-plugin</artifactId>
                <version>3.0.2</version>
                <configuration>
                    <modules>
                        <webModule>
                            [..]
                        </webModule>
                    </modules>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
</build>


<dependencies>
    <depdendency>
        <groupId>org.example</groupId>
        <artifactId>helloworld-model</artifactId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
</dependencies>

3. ejb/jar defined as jarModule

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-ear-plugin</artifactId>
                <version>3.0.2</version>
                <configuration>
                    <modules>
                        <webModule>
                            [..]
                        </webModule>
                        <jarModule>
                            <groupId>org.example</groupId>
                             <artifactId>helloworld-model</artifactId>
                            <version>1.0-SNAPSHOT</version>
                        </jarModule>
                    </modules>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
</build>

4. ejb/jar defined as dependency

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-ear-plugin</artifactId>
                <version>3.0.2</version>
                <configuration>
                    <modules>
                        <webModule>
                            [..]
                        </webModule>
                    </modules>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
</build>


<dependencies>
    <depdendency>
        <groupId>org.example</groupId>
        <artifactId>helloworld-model</artifactId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
</dependencies>

J Fabian Meier J Fabian Meier · Accepted Answer · 2020-10-01T09:39:23

To answer a part of your question:

EJB artifacts go to the main directory of the EAR, while JAR artifacts go to the lib dir.

Maven EAR Plugin Modules

1 Answers