* returns an arbitrary (but consistent) endpoint of the origin edge.
   */
  public final N nodeU() {
    return nodeU;
  }

  /**
   * Returns the node {@link #adjacentNode(Object) adjacent} to {@link #nodeU()} along the origin
   * edge. If this {@link EndpointPair} {@link #isOrdered()}, this is equal to {@link #target()}.
   */
  public final N nodeV() {
    return nodeV;
  }

  /**

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>maven.t01</groupId>
  <artifactId>p0</artifactId>
  <packaging>pom</packaging>
  <name>p0</name>
  <version>1.0</version>
  <organization>
    <name>p0-org</name>
  </organization>

specific language governing permissions and limitations
under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>maven.t02</groupId>
  <artifactId>p0</artifactId>
  <packaging>pom</packaging>
  <name>p0</name>
  <version>1.0</version>
  <organization>
    <name>Codehaus</name>
  </organization>

under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>aid</artifactId>
  <groupId>gid</groupId>
  <version>0.1</version>
  <packaging>pom</packaging>

  <profiles>
    <profile>
      <id>non-unique-id</id>
    </profile>
    <profile>
      <id>non-unique-id</id>
    </profile>
  </profiles>

under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>bleh</packaging>
  <dependencies>
    <dependency>
      <groupId>groupId</groupId>
      <version>1.0</version>
    </dependency>
  </dependencies>

"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>bleh</packaging>
  <dependencyManagement>
    <dependencies>
      <dependency>

under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>bleh</packaging>
  <dependencies>
    <dependency>
      <artifactId>artifactId</artifactId>
      <groupId>groupId</groupId>
    </dependency>
  </dependencies>

under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>bleh</packaging>
  <build>
    <plugins>
      <plugin>
        <version>1.0</version>
      </plugin>
    </plugins>
  </build>

under the License.
-->

<project>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>foo</artifactId>
  <groupId>foo</groupId>
  <version>99.44</version>
  <packaging>bleh</packaging>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-it-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

@GwtCompatible
@ElementTypesAreNonnullByDefault
public class TearDownStack implements TearDownAccepter {
  private static final Logger logger = Logger.getLogger(TearDownStack.class.getName());

  @VisibleForTesting final Object lock = new Object();

  @GuardedBy("lock")
  final LinkedList<TearDown> stack = new LinkedList<>();

  private final boolean suppressThrows;

  public TearDownStack() {
    this.suppressThrows = false;
  }