private static <T extends @Nullable Object> Entry<T, T> entry(T key, T value) {
    return new AbstractMap.SimpleImmutableEntry<>(key, value);
  }

  public void testCopyOfMutableEntryList() {
    List<Entry<String, String>> entryList =
        Arrays.asList(
            new AbstractMap.SimpleEntry<>("a", "1"), new AbstractMap.SimpleEntry<>("b", "2"));
    ImmutableMap<String, String> map = ImmutableMap.copyOf(entryList);

import com.google.j2objc.annotations.RetainedWith;
import com.google.j2objc.annotations.WeakOuter;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.AbstractMap;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.DoNotCall;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.util.AbstractMap;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Map;
import java.util.NavigableMap;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.function.BinaryOperator;

    return Synchronized.navigableMap(navigableMap);
  }

  /**
   * {@code AbstractMap} extension that makes it easy to cache customized keySet, values, and
   * entrySet views.
   */
  @GwtCompatible
  abstract static class ViewCachingAbstractMap<
          K extends @Nullable Object, V extends @Nullable Object>
      extends AbstractMap<K, V> {
    /**