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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <!-- name and version of the module -->
  <groupId>NameOfModule</groupId>
  <artifactId>NameOfModule</artifactId>
  <version>0.0.1-SNAPSHOT</version>

  <properties>
    <!-- set Vassal version here -->
    <vassal.version>3.7.5</vassal.version>

    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.vassalengine</groupId>
      <artifactId>vassal-app</artifactId>
      <version>${vassal.version}</version>
    </dependency>

    <!-- Add module dependencies which  are not part of Vassal here -->
    <dependency>
      <groupId>org.jdom</groupId>
      <artifactId>jdom2</artifactId>
      <version>2.0.5</version>
    </dependency>
  </dependencies>

  <repositories>
    <repository>
      <id>vassal-releases</id>
      <url>https://vassalengine.org/maven</url>
    </repository>
  </repositories>

  <build>
    <sourceDirectory>src</sourceDirectory>

    <!-- bundle files in dist/ into the module -->
    <resources>
      <!-- replace variables (e.g., ${project.version} in these files -->
      <resource>
        <directory>dist</directory>
        <filtering>true</filtering>
        <includes>
          <include>buildFile.xml</include>
          <include>moduledata</include>
        </includes>
      </resource>

      <!-- don't replace variables in these files -->
      <resource>
        <directory>dist</directory>
        <filtering>false</filtering>
        <excludes>
          <exclude>buildFile.xml</exclude>
          <exclude>moduledata</exclude>
        </excludes>
      </resource>
    </resources>

    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.11.0</version>
        <configuration>
          <showDeprecation>true</showDeprecation>
          <!-- Vassal requires compiling for Java 11 compatibility -->
          <release>11</release>
        </configuration>
      </plugin>

       <!--
           Uncomment the maven-shade-plugin to copy Java dependencies listed
           above in a <dependency> section into the module. Dependencies must
           be listed again in the <includes> section here to be packaged into
           the module. DO NOT enable the maven-shade-plugin without at least
           one dependency listed in <includes>.
       -->
<!--
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.5.1</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <artifactSet>
                <includes>
                  <include>org.jdom:jdom2</include>
                </includes>
              </artifactSet>
            </configuration>
          </execution>
        </executions>
      </plugin>
-->

      <!-- copy the .jar file maven packages to .vmod -->
      <plugin>
        <groupId>com.coderplus.maven.plugins</groupId>
        <artifactId>copy-rename-maven-plugin</artifactId>
        <version>1.0</version>
        <executions>
          <execution>
            <id>rename-file</id>
            <phase>package</phase>
            <goals>
              <goal>rename</goal>
            </goals>
            <configuration>
              <sourceFile>${project.build.directory}/${project.build.finalName}.jar</sourceFile>
              <destinationFile>${project.build.directory}/${project.build.finalName}.vmod</destinationFile>
            </configuration>
          </execution>
        </executions>
      </plugin>

    </plugins>
  </build>
</project>