return CollectCollectors.toImmutableRangeSet();
  }

  /**
   * Returns an empty immutable range set.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked")
  public static <C extends Comparable> ImmutableRangeSet<C> of() {
    return (ImmutableRangeSet<C>) EMPTY;
  }

  /**

    return CollectCollectors.toImmutableBiMap(keyFunction, valueFunction);
  }

  /**
   * Returns the empty bimap.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  // Casting to any type is safe because the set will never hold any elements.
  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableBiMap<K, V> of() {

 *
 * <p>Expressing the immutability guarantee directly in the type that user code references is a
 * powerful advantage. Although Java offers certain immutable collection factory methods, such as
 * {@link Collections#singleton(Object)} and <a
 * href="https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/util/Set.html#unmodifiable">{@code
 * Set.of}</a>, we recommend using <i>these</i> classes instead for this reason (as well as for

import org.apache.maven.api.cli.mvnup.UpgradeOptions;
import org.apache.maven.api.di.Inject;
import org.apache.maven.api.di.Named;
import org.apache.maven.api.di.Priority;
import org.apache.maven.api.di.Singleton;
import org.apache.maven.api.model.Build;
import org.apache.maven.api.model.Model;
import org.apache.maven.api.model.Parent;
import org.apache.maven.api.model.Plugin;
import org.apache.maven.api.model.PluginManagement;

    return CollectCollectors.toImmutableMultiset(elementFunction, countFunction);
  }

  /**
   * Returns the empty immutable multiset.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  @SuppressWarnings("unchecked") // all supported methods are covariant
  public static <E> ImmutableMultiset<E> of() {
    return (ImmutableMultiset<E>) RegularImmutableMultiset.EMPTY;
  }

  /**

    return CollectCollectors.flatteningToImmutableListMultimap(keyFunction, valuesFunction);
  }

  /**
   * Returns the empty multimap.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  // Casting is safe because the multimap will never hold any elements.
  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableListMultimap<K, V> of() {

    // ===================================================================================
    //                                                                           Singleton
    //                                                                           =========
    private static final UserDbm _instance = new UserDbm();

    private UserDbm() {
    }

 *
 * Use `new OkHttpClient()` to create a shared instance with the default settings:
 *
 * ```java
 * // The singleton HTTP client.
 * public final OkHttpClient client = new OkHttpClient();
 * ```
 *
 * Or use `new OkHttpClient.Builder()` to create a shared instance with custom settings:
 *
 * ```java
 * // The singleton HTTP client.
 * public final OkHttpClient client = new OkHttpClient.Builder()

    assertEvalsToFalse(nasty);

    Predicate<? super Integer> stillNasty = SerializableTester.reserializeAndAssert(nasty);

    assertEvalsToFalse(stillNasty);
  }

  // enum singleton pattern
  private enum TrimStringFunction implements Function<String, String> {
    INSTANCE;

    @Override
    public String apply(String string) {
      return whitespace().trimFrom(string);
    }
  }

                        Artifact.SCOPE_SYSTEM,
                        new File(getBasedir(), "pom.xml").getAbsolutePath());

        Set<Artifact> artifactDependencies =
                resolver.resolve(project, Collections.singleton(Artifact.SCOPE_COMPILE), session);
        assertEquals(1, artifactDependencies.size());
    }

    @Test
    void testSystemScopeDependencyIsPresentInTheCompileClasspathElements() throws Exception {