if (array.length == 0) {
      return "";
    }

    // For pre-sizing a builder, just get the right order of magnitude
    StringBuilder builder = new StringBuilder(array.length * 10);
    builder.append(array[0]);
    for (int i = 1; i < array.length; i++) {
      builder.append(separator).append(array[i]);
    }
    return builder.toString();
  }

  /**

    if (array.length == 0) {
      return "";
    }

    // For pre-sizing a builder, just get the right order of magnitude
    StringBuilder builder = new StringBuilder(array.length * 10);
    builder.append(array[0]);
    for (int i = 1; i < array.length; i++) {
      builder.append(separator).append(array[i]);
    }
    return builder.toString();
  }

  /**

  // but types are typically only Comparable to themselves).
  @SuppressWarnings({"rawtypes", "unchecked"})
  private static MinMaxPriorityQueue.Builder<Comparable<?>> rawtypeToWildcard(
      MinMaxPriorityQueue.Builder<Comparable> builder) {
    return (MinMaxPriorityQueue.Builder) builder;
  }

     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link SettingsBuilderException}.
     *
     * @return the problems that were encountered during the settings building, can be empty but never {@code null}
     */
    @Nonnull

     * {@link BuilderProblem.Severity#WARNING} and below are reported here. Problems with a higher severity level cause
     * the settings builder to fail with a {@link ToolchainsBuilderException}.
     *
     * @return the problems that were encountered during the settings building, can be empty but never {@code null}
     */
    @Nonnull

     * on the command line.
     */
    private List<MavenProject> projects;

    /**
     * The full set of projects before any potential constraining by --projects. Useful in the case where you want to
     * build a smaller set of projects but perform other operations in the context of your reactor.
     */
    private List<MavenProject> allProjects;

    private MavenProject topLevelProject;

    /**
     * Build timestamp format.
     *
     * @since 3.0.0
     */
    @Config(source = Config.Source.MODEL, defaultValue = "yyyy-MM-dd'T'HH:mm:ssXXX")
    public static final String MAVEN_BUILD_TIMESTAMP_FORMAT = "maven.build.timestamp.format";

    /**
     * User controlled relocations.

 This is strictly the immutable model for Maven toolchains in <<<org.apache.maven.api.toolchain>>> package.

 The following are generated from this model:

   * {{{./apidocs/index.html}Java sources}} with <<<Builder>>> inner classes for immutable instances creation.

 See also corresponding {{{../../maven-toolchain-model/index.html}Maven classical toolchains model documentation}}.

 * see {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.

 * directly; please see {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@IgnoreJRERequirement // We opt into library desugaring for our tests.