@Override
    public boolean removeAll(Collection<?> c) {
      synchronized (mutex) {
        return Iterators.removeAll(delegate().iterator(), c);
      }
    }

    @Override
    public boolean retainAll(Collection<?> c) {
      synchronized (mutex) {
        return Iterators.retainAll(delegate().iterator(), c);
      }
    }

    private static final long serialVersionUID = 0;
  }

    @Override
    public boolean removeAll(Collection<?> c) {
      synchronized (mutex) {
        return Iterators.removeAll(delegate().iterator(), c);
      }
    }

    @Override
    public boolean retainAll(Collection<?> c) {
      synchronized (mutex) {
        return Iterators.retainAll(delegate().iterator(), c);
      }
    }

    private static final long serialVersionUID = 0;
  }

    Set<Entry<Integer, String>> entries = map.entrySet();
    Iterator<Entry<Integer, String>> iterator = entries.iterator();
    Entry<Integer, String> entry = iterator.next();
    entry.setValue("two"); // changes the iterator's current entry value
    assertEquals("two", map.get(1));
    assertEquals(Integer.valueOf(1), map.inverse().get("two"));
    iterator.remove(); // removes the updated entry
    assertTrue(map.isEmpty());
  }

 * iteration ordering across rows and columns in the table's views. None of the view iterators
 * support {@link Iterator#remove}. If the table is modified after an iterator is created, the
 * iterator remains valid.
 *
 * <p>This class requires less memory than the {@link HashBasedTable} and {@link TreeBasedTable}
 * implementations, except when the table is sparse.
 *

import com.google.common.collect.testing.features.CollectionFeature;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.junit.Ignore;

/**
 * Tester to make sure the {@code iterator().remove()} implementation of {@code Multiset} works when
 * there are multiple occurrences of elements.
 *
 * @author Louis Wasserman
 */

        and:
        source.iterator().collect() == ["foo", "bar"]
    }

    def "can re-add an ordinary value after removal"() {
        when:
        source.add("a")
        source.add("b")
        source.remove("a")

        then:
        source.iterator().collect() == ["b"]

        when:
        source.add("a")

        then:
        source.iterator().collect() == ["b", "a"]
    }

      return (delegate != null)
          ? delegate.keySet().remove(o)
          : CompactHashMap.this.removeHelper(o) != NOT_FOUND;
    }

    @Override
    public Iterator<K> iterator() {
      return keySetIterator();
    }

    @Override
    public Spliterator<K> spliterator() {
      if (needsAllocArrays()) {

    Iterator<String> iterator = list.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("1", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("2", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("3", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("4", iterator.next());
    assertFalse(iterator.hasNext());

    Iterator<String> iterator = list.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("1", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("2", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("3", iterator.next());
    assertTrue(iterator.hasNext());
    assertEquals("4", iterator.next());
    assertFalse(iterator.hasNext());

    } else if (isEmpty()) {
      return true;
    }

    if (SortedIterables.hasSameComparator(comparator, that)) {
      Iterator<?> otherIterator = that.iterator();
      try {
        Iterator<E> iterator = iterator();
        while (iterator.hasNext()) {
          Object element = iterator.next();
          Object otherElement = otherIterator.next();