}

  public void testMapDifferenceEmptySingleton() {
    MapDifference<Integer, Integer> diff = Maps.difference(EMPTY, SINGLETON);
    assertFalse(diff.areEqual());
    assertEquals(EMPTY, diff.entriesOnlyOnLeft());
    assertEquals(SINGLETON, diff.entriesOnlyOnRight());
    assertEquals(EMPTY, diff.entriesInCommon());
    assertEquals(EMPTY, diff.entriesDiffering());

  }

  public void testMapDifferenceEmptySingleton() {
    MapDifference<Integer, Integer> diff = Maps.difference(EMPTY, SINGLETON);
    assertFalse(diff.areEqual());
    assertEquals(EMPTY, diff.entriesOnlyOnLeft());
    assertEquals(SINGLETON, diff.entriesOnlyOnRight());
    assertEquals(EMPTY, diff.entriesInCommon());
    assertEquals(EMPTY, diff.entriesDiffering());

import static com.google.common.truth.Truth.assertThat;
import static java.util.Arrays.asList;
import static java.util.Collections.emptyList;
import static java.util.Collections.emptySet;
import static java.util.Collections.singleton;
import static java.util.Collections.singletonList;

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

                    .authority(authority)
                    .build();

            final RefreshTokenParameters parameters =
                    RefreshTokenParameters.builder(Collections.singleton("https://graph.microsoft.com/.default"), refreshToken).build();

            final IAuthenticationResult result = app.acquireToken(parameters).get(acquisitionTimeout, TimeUnit.MILLISECONDS);
            if (result == null) {

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.project;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.model.building;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.model.validation;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import java.io.File;
import java.util.Arrays;
import java.util.Deque;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

            return result;
        } catch (Exception e) {
            log.warn("Failed to create fresh context, using singleton", e);
            try {
                // Fallback to singleton with fresh auth
                NtlmPasswordAuthentication auth =
                        new NtlmPasswordAuthentication(SingletonContext.getInstance(), WORKGROUP, USERNAME, PASSWORD);

 *
 * Use `new OkHttpClient()` to create a shared instance with the default settings:
 *
 * ```java
 * // The singleton HTTP client.
 * public final OkHttpClient client = new OkHttpClient();
 * ```
 *
 * Or use `new OkHttpClient.Builder()` to create a shared instance with custom settings:
 *
 * ```java
 * // The singleton HTTP client.
 * public final OkHttpClient client = new OkHttpClient.Builder()

  @SuppressWarnings("unchecked")
  static <T extends @Nullable Object> UnmodifiableListIterator<T> emptyListIterator() {
    return (UnmodifiableListIterator<T>) ArrayItr.EMPTY;
  }

  /**
   * This is an enum singleton rather than an anonymous class so ProGuard can figure out it's only
   * referenced by emptyModifiableIterator().
   */
  private enum EmptyModifiableIterator implements Iterator<Object> {
    INSTANCE;

    @Override