throw new NoGoalSpecifiedException("No goals have been specified for this build."
                        + " You must specify a valid lifecycle phase or a goal in the format <plugin-prefix>:<goal> or"
                        + " <plugin-group-id>:<plugin-artifact-id>[:<plugin-version>]:<goal>."
                        + " Available lifecycle phases are: " + defaultLifeCycles.getLifecyclePhaseList() + ".");
            }

import org.apache.maven.api.di.Named;
import org.apache.maven.api.di.Singleton;
import org.apache.maven.cling.invoker.mvnup.Goal;
import org.apache.maven.cling.invoker.mvnup.UpgradeContext;

/**
 * The "help" goal implementation.
 */
@Named("help")
@Singleton
public class Help implements Goal {

    @Override
    public int execute(UpgradeContext context) throws Exception {

        <artifactId>maven-it-plugin</artifactId>
        <version>0.1</version>
        <executions>
          <execution>
            <goals>
              <goal>generate-metadata</goal>
              <goal>generate-test-metadata</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>

        <version>${maven-bundle-plugin.version}</version>
        <executions>
          <execution>
            <id>bundle-manifest</id>
            <phase>process-classes</phase>
            <goals>
              <goal>manifest</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <instructions>

          </params>
        </configuration>
        <executions>
          <execution>
            <id>modello</id>
            <goals>
              <goal>velocity</goal>
              <goal>xdoc</goal>
              <goal>xsd</goal>
            </goals>
            <phase>generate-resources</phase>
          </execution>
        </executions>
      </plugin>
      <plugin>

          </params>
        </configuration>
        <executions>
          <execution>
            <id>modello</id>
            <goals>
              <goal>velocity</goal>
              <goal>xdoc</goal>
              <goal>xsd</goal>
            </goals>
            <phase>generate-resources</phase>
          </execution>
        </executions>
      </plugin>
      <plugin>

          </params>
        </configuration>
        <executions>
          <execution>
            <id>modello</id>
            <goals>
              <goal>velocity</goal>
              <goal>xdoc</goal>
              <goal>xsd</goal>
            </goals>
            <phase>generate-sources</phase>
          </execution>
        </executions>
      </plugin>
      <plugin>

            Goal goal = context.goals.get(goalName);
            if (goal == null) {
                return badGoalsErrorMessage("Unknown goal: " + goalName, context);
            }

            return goal.execute(context);
        } catch (InterruptedException | InterruptedIOException | UserInterruptException e) {
            context.logger.error("Goal canceled by user.");
            return CANCELED;

              <goals>
                <goal>xdoc</goal>
                <goal>xsd</goal>
              </goals>
            </execution>
            <execution>
              <id>standard</id>
              <goals>
                <goal>java</goal>
                <goal>xpp3-reader</goal>
                <goal>xpp3-writer</goal>
              </goals>
            </execution>

        </configuration>
        <executions>
          <execution>
            <id>modello</id>
            <goals>
              <goal>velocity</goal>
              <goal>xdoc</goal>
              <goal>xsd</goal>
            </goals>
            <phase>generate-sources</phase>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>