</description>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.its.plugins</groupId>
        <artifactId>maven-it-plugin-class-loader</artifactId>
        <version>2.1-SNAPSHOT</version>
        <dependencies>
          <dependency>
            <groupId>org.apache.maven.its.mng3906</groupId>
            <artifactId>c</artifactId>
            <version>0.1</version>
          </dependency>

    public UnresolvableModelException(
            String message, String groupId, String artifactId, String version, Throwable cause) {
        super(message, cause);
        this.groupId = (groupId != null) ? groupId : "";
        this.artifactId = (artifactId != null) ? artifactId : "";
        this.version = (version != null) ? version : "";
    }

    /**
     * Creates a new exception with specified detail message.
     *

    }

    @Override
    public Object get(String groupId, String artifactId, String version, String tag) {
        return cache.get(session, new Key(groupId, artifactId, version, tag));
    }

    @Override
    public void put(String groupId, String artifactId, String version, String tag, Object data) {
        cache.put(session, new Key(groupId, artifactId, version, tag), data);
    }

    static class Key {

<project>
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.apache.maven.test</groupId>
  <artifactId>project-with-build-extensions-plugin</artifactId>
  <version>1.0</version>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.its.plugins</groupId>
        <artifactId>maven-it-plugin</artifactId>
        <version>0.1</version>
        <extensions>true</extensions>
        <executions>
          <execution>

-->

<project>
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>org.apache.maven.its.mng6300</groupId>
    <artifactId>test</artifactId>
    <version>1.0</version>
  </parent>
  <artifactId>mng6300-war</artifactId>
  <packaging>war</packaging>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-war-plugin</artifactId>
        <configuration>

  </description>

  <build>
    <extensions>
      <extension>
        <groupId>org.apache.maven.its.mng3899</groupId>
        <artifactId>a</artifactId>
        <version>0.1</version>
      </extension>
      <extension>
        <groupId>org.apache.maven.its.mng3899</groupId>
        <artifactId>c</artifactId>
        <version>0.1</version>
      </extension>
    </extensions>
  </build>

     */
    public String getGroupId() {
        return (groupId != null) ? groupId : "";
    }

    /**
     * Sets the effective group identifier of the model.
     *
     * @param groupId The effective group identifier of the model, may be {@code null}.
     */
    public void setGroupId(String groupId) {
        this.groupId = groupId;
    }

    /**

     */
    private String getPluginKey(Plugin plugin) {
        String groupId = plugin.getGroupId();
        String artifactId = plugin.getArtifactId();

        // Default groupId for Maven plugins
        if (groupId == null && artifactId != null && artifactId.startsWith(MAVEN_PLUGIN_PREFIX)) {
            groupId = DEFAULT_MAVEN_PLUGIN_GROUP_ID;
        }

  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>ut.simple</groupId>
    <artifactId>parent</artifactId>
    <version>1.0</version>
  </parent>

  <artifactId>artifact</artifactId>

  <name>Simple Unit Test Artifact</name>

  <dependencies>
    <dependency>
      <groupId>ut.simple</groupId>
      <artifactId>dependency</artifactId>
    </dependency>
    <dependency>

  <groupId>maven-test</groupId>
  <artifactId>t06-b</artifactId>
  <packaging>jar</packaging>
  <version>1.0</version>
  <dependencies>
    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>t06-c</artifactId>
      <version>1.0</version>
      <type>jar</type>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>maven-test</groupId>