}

  /*
   * Tests that we workaround GWT bug #3621 (or that it is already fixed).
   *
   * A call to of() with a parameter that is not a plain Object[] (here,
   * Interface[]) creates a RegularImmutableSortedSet backed by an array of that
   * type. Later, RegularImmutableSortedSet.toArray() calls System.arraycopy()

   * using {@link Collections#list}.
   *
   * <p><b>Java 9 users:</b> use {@code enumeration.asIterator()} instead, unless it is important to
   * return an {@code UnmodifiableIterator} instead of a plain {@code Iterator}.
   */
  public static <T extends @Nullable Object> UnmodifiableIterator<T> forEnumeration(
      Enumeration<T> enumeration) {
    checkNotNull(enumeration);

   * normally derive from {@code Map<Object, Object>}, but they typically contain strings, which is
   * awkward. This method lets you get a plain-old-{@code Map} out of a {@code Properties}.
   *
   * @param properties a {@code Properties} object to be converted
   * @return an immutable map containing all the entries in {@code properties}

        .addEqualityGroup(
            MediaType.create("text", "plain"),
            MediaType.create("TEXT", "PLAIN"),
            MediaType.parse("text/plain"),
            MediaType.parse("TEXT/PLAIN"),
            MediaType.parse("text /plain"),
            MediaType.parse("TEXT/ plain"),
            MediaType.parse("text / plain"),
            MediaType.create("text", "plain").withParameter("a", "1").withoutParameters())

        .addEqualityGroup(
            MediaType.create("text", "plain"),
            MediaType.create("TEXT", "PLAIN"),
            MediaType.parse("text/plain"),
            MediaType.parse("TEXT/PLAIN"),
            MediaType.parse("text /plain"),
            MediaType.parse("TEXT/ plain"),
            MediaType.parse("text / plain"),
            MediaType.create("text", "plain").withParameter("a", "1").withoutParameters())

   *
   * <p>For example:
   *
   * <pre>{@code
   * PLAIN_TEXT_UTF_8.is(PLAIN_TEXT_UTF_8) // true
   * PLAIN_TEXT_UTF_8.is(HTML_UTF_8) // false
   * PLAIN_TEXT_UTF_8.is(ANY_TYPE) // true
   * PLAIN_TEXT_UTF_8.is(ANY_TEXT_TYPE) // true
   * PLAIN_TEXT_UTF_8.is(ANY_IMAGE_TYPE) // false
   * PLAIN_TEXT_UTF_8.is(ANY_TEXT_TYPE.withCharset(UTF_8)) // true
   * PLAIN_TEXT_UTF_8.withoutParameters().is(ANY_TEXT_TYPE.withCharset(UTF_8)) // false

import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicBoolean;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Utilities necessary for working with libraries that supply plain {@link Future} instances. Note
 * that, whenever possible, it is strongly preferred to modify those libraries to return {@code
 * ListenableFuture} directly.
 *

@GwtCompatible
@ElementTypesAreNonnullByDefault
final class NullnessCasts {
  /**
   * Accepts a {@code @Nullable T} and returns a plain {@code T}, without performing any check that
   * that conversion is safe.
   *
   * <p>This method is intended to help with usages of type parameters that have {@linkplain

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Outer class that exists solely to let us write {@code Partially.GwtIncompatible} instead of plain
 * {@code GwtIncompatible}. This is more accurate for {@link Futures#catching}, which is available
 * under GWT but with a slightly different signature.
 *

    return delegate().get(key, valueLoader);
  }

  /** @since 11.0 */
  @Override
  /*
   * <? extends Object> is mostly the same as <?> to plain Java. But to nullness checkers, they
   * differ: <? extends Object> means "non-null types," while <?> means "all types."
   */
  public ImmutableMap<K, V> getAllPresent(Iterable<? extends Object> keys) {