import java.lang.annotation.Inherited;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.Collection;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * When describing the features of the collection produced by a given generator (i.e. in a call to
 * {@link
 * com.google.common.collect.testing.FeatureSpecificTestSuiteBuilder#withFeatures(Feature...)}),

  }

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

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

import org.jspecify.annotations.Nullable;

/**
 * A callback for accepting the results of a {@link java.util.concurrent.Future} computation
 * asynchronously.
 *
 * <p>To attach to a {@link ListenableFuture} use {@link Futures#addCallback}.
 *
 * @author Anthony Zana
 * @since 10.0
 */
@GwtCompatible
public interface FutureCallback<V extends @Nullable Object> {

import java.util.ListIterator;
import org.jspecify.annotations.Nullable;

/**
 * A list iterator that does not support {@link #remove}, {@link #add}, or {@link #set}.
 *
 * @since 7.0
 * @author Louis Wasserman
 */
@GwtCompatible
public abstract class UnmodifiableListIterator<E extends @Nullable Object>
    extends UnmodifiableIterator<E> implements ListIterator<E> {

 * the License.
 */

package com.google.common.base;

import com.google.common.annotations.GwtIncompatible;
import org.jspecify.annotations.Nullable;

/**
 * Represents a {@linkplain System#getProperties() standard system property}.
 *
 * @author Kurt Alfred Kluever
 * @since 15.0
 */
@GwtIncompatible // java.lang.System#getProperty

import com.google.common.annotations.GwtCompatible;
import java.util.concurrent.Future;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Classes and futures used in {@link FuturesGetCheckedTest} and {@link FuturesGetUncheckedTest}.
 */
@GwtCompatible
@NullUnmarked
final class FuturesGetCheckedInputs {

import com.google.j2objc.annotations.Weak;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.concurrent.Executor;
import org.jspecify.annotations.Nullable;

/**
 * A subscriber method on a specific object, plus the executor that should be used for dispatching
 * events to it.
 *
 * <p>Two subscribers are equivalent when they refer to the same method on the same object (not

import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/** Replacements for JUnit's {@code assertThrows} that work under GWT/J2CL. */
@GwtCompatible
@NullMarked
final class ReflectionFreeAssertThrows {
  interface ThrowingRunnable {
    void run() throws Throwable;
  }

  interface ThrowingSupplier {
    @Nullable Object get() throws Throwable;
  }

  @CanIgnoreReturnValue

import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/** Replacements for JUnit's {@code assertThrows} that work under GWT/J2CL. */
@GwtCompatible
@NullMarked
final class ReflectionFreeAssertThrows {
  interface ThrowingRunnable {
    void run() throws Throwable;
  }

  interface ThrowingSupplier {
    @Nullable Object get() throws Throwable;
  }

  @CanIgnoreReturnValue

import java.nio.charset.Charset;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import junit.framework.AssertionFailedError;
import junit.framework.TestCase;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link ForwardingWrapperTester}. Live in a different package to detect reflection
 * access issues, if any.
 *
 * @author Ben Yu
 */
public class ForwardingWrapperTesterTest extends TestCase {