private final Adder adder;

    FailsToForwardReturnValue(Adder adder) {
      this.adder = adder;
    }

    @Override
    public int add(int a, int b) {
      return adder.add(a, b) + 1;
    }

    @Override
    public String toString() {
      return adder.toString();
    }
  }

  private static class FailsToPropagateException implements Adder {

 *
 * <p>Multimaps are commonly used in places where a {@code Map<K, Collection<V>>} would otherwise
 * have appeared. The differences include:
 *
 * <ul>
 *   <li>There is no need to populate an empty collection before adding an entry with {@link #put
 *       put}.
 *   <li>{@code get} never returns {@code null}, only an empty collection.
 *   <li>A key is contained in the multimap if and only if it maps to at least one value. Any

    }
  }

  /** Test equalObjects after adding multiple instances at once with a null */
  public void testAddTwoEqualObjectsAtOnceWithNull() {
    try {
      equalsTester.addEqualityGroup(reference, equalObject1, null);
      fail("Should fail on null equal object");
    } catch (NullPointerException e) {
    }
  }

  /** Test adding null equal object yields error */
  public void testAddNullEqualObject() {

 *
 * @author Chris Povirk
 */
/*
 * The whole thing is really @GwtIncompatible, but GwtJUnitConvertedTestModule doesn't have a
 * parameter for non-GWT, non-test files, and it didn't seem worth adding one for this unusual case.
 */
@GwtCompatible(emulated = true)
final class LenientSerializableTester {
  /*
   * TODO(cpovirk): move this to c.g.c.testing if we allow for c.g.c.annotations dependencies so

      ImmutableSet.of("foo.bar.google.com", "a.b.co.uk", "x.y.ca.us", "a.b.blogspot.com");

  private static final ImmutableSet<String> VALID_IP_ADDRS =
      ImmutableSet.of("1.2.3.4", "127.0.0.1", "::1", "2001:db8::1");

  private static final ImmutableSet<String> INVALID_IP_ADDRS =
      ImmutableSet.of(
          "", "1", "1.2.3", "...", "1.2.3.4.5", "400.500.600.700", ":", ":::1", "2001:db8:");

 *       a more precisely named annotation?
 *   <li>While a dependency on Android ought to be easy if it's for annotations only, it will
 *       probably require adding the dep to various ACLs, license files, and Proguard
 *       configurations, and there's always the potential that something will go wrong. It
 *       <i>probably</i> won't, since the deps are needed only in tests (and maybe someday in

3.  Pull requests are not merged directly into the master branch.
4.  Code contributions require signing a Google CLA.

API changes
-----------

We make changes to Guava's public [APIs][], including adding new APIs, very
carefully. Because of this, if you're interested in seeing a new feature in
Guava, the best approach is to create an [issue][] (or comment on an existing

 * {@code asMap} has a few subtleties. As long as the set of keys remains unchanged, adding or
 * removing mappings does not affect the key iteration order. However, if you remove all values
 * associated with a key and then add the key back to the multimap, that key will come last in the
 * key iteration order.
 *
 * <p>The multimap does not store duplicate key-value pairs. Adding a new key-value pair equal to an
 * existing key-value pair has no effect.
 *

import java.util.Map.Entry;
import java.util.Set;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@code Multimap} that cannot hold duplicate key-value pairs. Adding a key-value pair that's
 * already in the multimap has no effect. See the {@link Multimap} documentation for information
 * common to all multimaps.
 *

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * CompactLinkedHashSet is an implementation of a Set, which a predictable iteration order that
 * matches the insertion order. All optional operations (adding and removing) are supported. All
 * elements, including {@code null}, are permitted.
 *
 * <p>{@code contains(x)}, {@code add(x)} and {@code remove(x)}, are all (expected and amortized)