Multi-module projects and maven central

Question

I am planning a multi-module maven project.

Parent POM defines two modules, A and B

• Module A needs to be executable from the command line to show an AWT JDialog.
• Module B will be a normal jar whose 12-odd dependencies are downloaded by the client (i.e. not packaged)
• Module B needs to be dependent on module A.
• Want to keep jars as small as possible for distribution on Maven Central.

My Questions:
1. Is a multi-module maven project the correct approach to achieve these aims?
2. Do both modules needs to be published separately to maven central?

Answer 1

This looks like a typical scenario for multi-module build.

.
├── mod-a
│   └── pom.xml
├── mod-b
│   └── pom.xml
└── pom.xml (parent)

The parent contains simply a list of module (two) which looks similar like this:

<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>
    <groupId>com.soebes.smpp</groupId>
    <artifactId>smpp</artifactId>
    <version>0.7.1</version>
  </parent>

  <groupId>com.soebes.training.first</groupId>
  <artifactId>project-parent</artifactId>
  <version>0.1.0-SNAPSHOT</version>
  <packaging>pom</packaging>

  <name>Project : Parent</name>

  <scm>
   Define the SCM information here...
  </scm>

  <modules>
    <module>mod-a</module>
    <module>mod-b</module>
  </modules>

</project>

Every child should look similar like this:

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>com.soebes.training.first</groupId>
    <artifactId>project-parent</artifactId>
    <version>0.1.0-SNAPSHOT</version>
  </parent>

  <name>Project : Mod-A</name>
  <artifactId>mod-a</artifactId>

</project>

And you module-b should look like this:

<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>com.soebes.training.first</groupId>
    <artifactId>project-parent</artifactId>
    <version>0.1.0-SNAPSHOT</version>
  </parent>

  <name>Project : Mod-B</name>
  <artifactId>mod-b</artifactId>

  <dependencies>
    <dependency>
      <groupId>${project.groupId}</groupId>
      <artifactId>mod-a</artifactId>
      <version>${project.version}</version>
    </dependency>
  </dependencies>

</project>

Now you can build from parent module and all these should be deployed to central and there is no need to do this separately you can do that in one go from parent...