private Iterables() {}

  /** Returns an unmodifiable view of {@code iterable}. */
  public static <T extends @Nullable Object> Iterable<T> unmodifiableIterable(
      Iterable<? extends T> iterable) {
    checkNotNull(iterable);
    if (iterable instanceof UnmodifiableIterable || iterable instanceof ImmutableCollection) {
      @SuppressWarnings("unchecked") // Since it's unmodifiable, the covariant cast is safe

  private Iterables() {}

  /** Returns an unmodifiable view of {@code iterable}. */
  public static <T extends @Nullable Object> Iterable<T> unmodifiableIterable(
      Iterable<? extends T> iterable) {
    checkNotNull(iterable);
    if (iterable instanceof UnmodifiableIterable || iterable instanceof ImmutableCollection) {
      @SuppressWarnings("unchecked") // Since it's unmodifiable, the covariant cast is safe

 * 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;

import com.google.common.annotations.GwtIncompatible;
import java.lang.reflect.InvocationHandler;

    Iterable<String> iterable = Iterables.unmodifiableIterable(list);
    Iterable<String> iterable2 = Iterables.unmodifiableIterable(iterable);
    assertThat(iterable2).isSameInstanceAs(iterable);
    ImmutableList<String> immutableList = ImmutableList.of("a", "b", "c");
    assertThat(Iterables.unmodifiableIterable(immutableList)).isSameInstanceAs(immutableList);
    assertThat(Iterables.unmodifiableIterable((List<String>) immutableList))