* the map. Besides being slightly shorter than code that uses {@link #getMap()}, it also ensures
   * that callers don't pass an {@link Entry} by mistake.
   */
  protected V get(K key) {
    return getMap().get(key);
  }

  protected final K k0() {
    return e0().getKey();
  }

  protected final V v0() {
    return e0().getValue();
  }

    // together and this really shows the problem of constructing a sensible default configuration but
    // it's all encapsulated here so it appears normalized to the POM builder.

    // We are going to take the project packaging and find all plugin in the default lifecycle and create
    // fully populated Plugin objects, including executions with goals and default configuration taken
    // from the plugin.xml inside a plugin.
    //

    assertThat(Comparators.max(1, 2, reverse)).isEqualTo(1);
    assertThat(Comparators.max(2, 1, reverse)).isEqualTo(1);
  }

  /**
   * Fails compilation if the signature of min and max is changed to take {@code Comparator<T>}
   * instead of {@code Comparator<? super T>}.
   */
  public void testMinMaxWithSupertypeComparator() {
    Comparator<Number> numberComparator =

                    break;
                }
            }

            if (basedirExpr != null) {
                if (s.length() > basedirExpr.length()) {
                    // Take out basedir expression and the leading slash
                    s = chopLeadingFileSeparator(s.substring(basedirExpr.length()));
                } else {
                    s = ".";
                }
            }

    assertThat(Comparators.max(1, 2, reverse)).isEqualTo(1);
    assertThat(Comparators.max(2, 1, reverse)).isEqualTo(1);
  }

  /**
   * Fails compilation if the signature of min and max is changed to take {@code Comparator<T>}
   * instead of {@code Comparator<? super T>}.
   */
  public void testMinMaxWithSupertypeComparator() {
    Comparator<Number> numberComparator =

   *       terminate whichever thread happens to trigger the execution.
   * </ul>
   *
   * A specific warning about locking: Code that executes user-supplied tasks, such as {@code
   * ListenableFuture} listeners, should take care not to do so while holding a lock. Additionally,
   * as a further line of defense, prefer not to perform any locking inside a task that will be run

     * all other executions until finished.
     * We also lock on a given project to forbid a forked lifecycle to be executed concurrently with the project.
     * TODO: ideally, the builder should take care of the ordering in a smarter way
     * TODO: and concurrency issues fixed with MNG-7157
     */
    private class ProjectLock implements AutoCloseable {
        final Lock acquiredAggregatorLock;

    ImmutableSet.Builder<ImmutableList<Class<?>>> allOverloads = ImmutableSet.builder();
    // The first two are for the overloads that don't take formatting args, e.g.
    // checkArgument(boolean) and checkArgument(boolean, Object)
    allOverloads.add(ImmutableList.<Class<?>>of(predicateType));
    allOverloads.add(ImmutableList.<Class<?>>of(predicateType, Object.class));

    List<?> exp = copyToList(expected);
    List<?> act = copyToList(actual);
    String actString = act.toString();

    // Of course we could take pains to give the complete description of the
    // problem on any failure.

    // Yeah it's n^2.
    for (Object object : exp) {
      if (!act.remove(object)) {
        Assert.fail(

            boolean isBlankVersion = descriptor.getRequiredMavenVersion() == null
                    || descriptor.getRequiredMavenVersion().trim().isEmpty();

            if (isBlankVersion) {
                // only take value from underlying POM if plugin descriptor has no explicit Maven requirement
                descriptor.setRequiredMavenVersion(artifact.getProperty("requiredMavenVersion", null));
            }