Iterator<String> iterator = singletonList("foo").iterator();
    assertEquals("foo", getOnlyElement(iterator));
  }

  public void testGetOnlyElement_noDefault_empty() {
    Iterator<String> iterator = emptyIterator();
    assertThrows(NoSuchElementException.class, () -> getOnlyElement(iterator));
  }

  public void testGetOnlyElement_noDefault_moreThanOneLessThanFiveElements() {

    Iterator<String> iterator = singletonList("foo").iterator();
    assertEquals("foo", getOnlyElement(iterator));
  }

  public void testGetOnlyElement_noDefault_empty() {
    Iterator<String> iterator = emptyIterator();
    assertThrows(NoSuchElementException.class, () -> getOnlyElement(iterator));
  }

  public void testGetOnlyElement_noDefault_moreThanOneLessThanFiveElements() {

 * limitations under the License.
 */

package com.google.common.collect.testing.google;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.Iterables.getOnlyElement;
import static com.google.common.collect.testing.Helpers.mapEntry;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.ImmutableMap;

  }

  public void testGetOnlyElement_withDefault_singleton() {
    Iterable<String> iterable = singletonList("foo");
    assertEquals("foo", getOnlyElement(iterable, "bar"));
  }

  public void testGetOnlyElement_withDefault_empty() {
    Iterable<String> iterable = emptyList();
    assertEquals("bar", getOnlyElement(iterable, "bar"));
  }

import static com.google.common.base.Preconditions.checkState;
import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;
import static com.google.common.collect.Iterables.getOnlyElement;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.Serializable;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.EnumMap;

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.Iterables.getOnlyElement;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;

   * @throws IllegalArgumentException if the iterable contains multiple elements
   */
  @ParametricNullness
  public static <T extends @Nullable Object> T getOnlyElement(Iterable<T> iterable) {
    return Iterators.getOnlyElement(iterable.iterator());
  }

  /**
   * Returns the single element contained in {@code iterable}, or {@code defaultValue} if the
   * iterable is empty.
   *

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.Iterables.getOnlyElement;
import static com.google.common.collect.Iterables.unmodifiableIterable;
import static com.google.common.reflect.Reflection.newProxy;
import static java.util.Arrays.asList;

    List<Future<String>> results;

    results = service.invokeAll(callables);
    assertThat(getOnlyElement(results)).isInstanceOf(TrustedListenableFutureTask.class);

    results = service.invokeAll(callables, 1, SECONDS);
    assertThat(getOnlyElement(results)).isInstanceOf(TrustedListenableFutureTask.class);

    /*
     * TODO(cpovirk): move ForwardingTestCase somewhere common, and use it to

  }

  public void testGetOnlyElement_withDefault_singleton() {
    Iterable<String> iterable = singletonList("foo");
    assertEquals("foo", getOnlyElement(iterable, "bar"));
  }

  public void testGetOnlyElement_withDefault_empty() {
    Iterable<String> iterable = emptyList();
    assertEquals("bar", getOnlyElement(iterable, "bar"));
  }