public void testCopyOfNullKey() {
    ArrayListMultimap<@Nullable String, Integer> input = ArrayListMultimap.create();
    input.put(null, 1);
    assertThrows(
        NullPointerException.class,
        () -> ImmutableListMultimap.copyOf((ArrayListMultimap<String, Integer>) input));
  }

  public void testCopyOfNullValue() {
    ArrayListMultimap<String, @Nullable Integer> input = ArrayListMultimap.create();

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Implementation of {@link Multimaps#filterEntries(Multimap, Predicate)}.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
class FilteredEntryMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimap<K, V> implements FilteredMultimap<K, V> {

   * <p>Cancellation does not propagate from the output future to a callable that has begun to
   * execute, but if the output future is cancelled before {@link Callable#call()} is invoked,
   * {@link Callable#call()} will not be invoked.
   */
  public <T extends @Nullable Object> ListenableFuture<T> submit(
      Callable<T> callable, Executor executor) {
    checkNotNull(callable);
    checkNotNull(executor);
    return submitAsync(

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.ListIterator;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A list iterator which forwards all its method calls to another list iterator. Subclasses should
 * override one or more methods to modify the behavior of the backing iterator as desired per the <a

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.util.function.Consumer;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An {@link ImmutableAsList} implementation specialized for when the delegate collection is already
 * backed by an {@code ImmutableList} or array.
 *
 * @author Louis Wasserman
 */

import jsinterop.annotations.JsMethod;
import jsinterop.annotations.JsPackage;
import jsinterop.annotations.JsProperty;
import jsinterop.annotations.JsType;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Minimal GWT emulation of {@code com.google.common.collect.Platform}.
 *
 * @author Hayward Chan
 */
final class Platform {
  static <K, V> Map<K, V> newHashMapWithExpectedSize(int expectedSize) {

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Based on what a {@link Type} is, dispatch it to the corresponding {@code visit*} method. By
 * default, no recursion is done for type arguments or type bounds. But subclasses can opt to do

import java.io.Serializable;
import java.util.Map.Entry;
import java.util.Spliterator;
import java.util.function.Consumer;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * {@code entrySet()} implementation for {@link ImmutableMap}.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault

import com.google.common.collect.testing.WrongType;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.junit.Ignore;

/**
 * Common parent class for {@link ListIndexOfTester} and {@link ListLastIndexOfTester}.
 *
 * @author Chris Povirk
 */
@GwtCompatible

import com.google.errorprone.annotations.concurrent.LazyInit;
import java.util.Comparator;
import java.util.NavigableSet;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Implementation of {@link Multisets#unmodifiableSortedMultiset(SortedMultiset)}, split out into
 * its own file so it can be GWT emulated (to deal with the differing elementSet() types in GWT and
 * non-GWT).
 *