if ("JAR".equals(packaging)) {
            plugins = new LinkedHashSet<>();

            plugins.add(newPlugin("maven-compiler-plugin", "compile", "testCompile"));
            plugins.add(newPlugin("maven-resources-plugin", "resources", "testResources"));
            plugins.add(newPlugin("maven-surefire-plugin", "test"));
            plugins.add(newPlugin("maven-jar-plugin", "jar"));

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>maven-test</groupId>
  <artifactId>t07-c</artifactId>
  <packaging>jar</packaging>
  <version>1.0</version>
  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t07-d</artifactId>
      <version>1.1</version>
      <type>jar</type>
      <scope>compile</scope>
      <optional>true</optional>
    </dependency>
  </dependencies>

    //
    // or we can show it graphically as:
    //
    // p1 ---> p0 --> super model
    //
    // p1 has a depMgmt section that specifies versions 1.0 of jars "a" & "b"
    // jar "a" has a transitive dependency on 2.0 of jar "b", but maven should
    // prefer to use version 1.0.
    //
    // ----------------------------------------------------------------------

    @Test

        <artifactId>maven-jar-plugin</artifactId>
        <executions>
          <execution>
            <id>package-sisu</id>
            <goals>
              <goal>jar</goal>
            </goals>
            <phase>package</phase>
            <configuration>
              <classifier>sisu</classifier>
              <classesDirectory>${project.build.directory}/jar-sisu</classesDirectory>

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>maven-test</groupId>
  <artifactId>t08-a</artifactId>
  <packaging>jar</packaging>
  <version>1.0</version>
  <repositories>
    <repository>
      <id>central</id>
      <name>Fake Maven Central Repository</name>
      <url>file://dummy</url>
    </repository>
  </repositories>
  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>

@Immutable
public interface DependencyCoordinates extends ArtifactCoordinates {
    /**
     * {@return the type of the dependency}
     * A dependency can be a <abbr>JAR</abbr> file,
     * a modular-<abbr>JAR</abbr> if it is intended to be placed on the module path,
     * a <abbr>JAR</abbr> containing test classes, a POM file, <i>etc.</i>
     */
    @Nonnull
    Type getType();

    /**

        <jdkHome>${env.JAVA_HOME}</jdkHome>
        <toolsJar>lib/tools.jar</toolsJar>
     </configuration>
  </toolchain>
  <toolchain>
     <type>jdk</type>
     <provides>
         <version>1.6</version>
         <vendor>sun</vendor>
     </provides>
     <configuration>
        <jdkHome>${env.JAVA_HOME}</jdkHome>
        <toolsJar>lib/classes.jar</toolsJar>
     </configuration>
  </toolchain>

        if ("JAR".equals(packaging)) {
            plugins = new LinkedHashSet<>();

            plugins.add(newPlugin("maven-compiler-plugin", "compile", "testCompile"));
            plugins.add(newPlugin("maven-resources-plugin", "resources", "testResources"));
            plugins.add(newPlugin("maven-surefire-plugin", "test"));
            plugins.add(newPlugin("maven-jar-plugin", "jar"));

      <![CDATA[
      This is a list of attachments to the main artifact produced by building the current POM.
      Attachments are derived works, based on the main build process, such as an ejb-client jar,
      project sources jar, etc.
    ]]></description>
  </expression>
</expressions>

     */
    public String getExtensionDescriptorLocation() {
        return "META-INF/maven/extension.xml";
    }

    /**
     * Extracts the extension descriptor (if any) from the specified JAR file.
     *
     * @param extensionJar The JAR file or directory to extract the descriptor from, must not be {@code null}.
     * @return The extracted descriptor or {@code null} if no descriptor was found.