// Comprehensive test to verify all methods return expected values
        FessJsonResourceProvider testProvider = new FessJsonResourceProvider();

        // Verify nulls suppression is enabled
        assertTrue("Nulls should be suppressed", testProvider.isNullsSuppressed());

        // Verify pretty print is enabled
        assertFalse("Pretty print should not be suppressed", testProvider.isPrettyPrintSuppressed());

      new RegularImmutableSet<>(EMPTY_ARRAY, 0, EMPTY_ARRAY, 0, 0);

  // The first `size` elements are non-null.
  @VisibleForTesting final transient @Nullable Object[] elements;
  private final transient int hashCode;
  // the same values as `elements` in hashed positions (plus nulls)
  @VisibleForTesting final transient @Nullable Object[] table;
  // 'and' with an int to get a valid table index.

 * exceptions whenever it can.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public class MinimalCollection<E extends @Nullable Object> extends AbstractCollection<E> {
  // TODO: expose allow nulls parameter?

  public static <E extends @Nullable Object> MinimalCollection<E> of(E... contents) {
    return new MinimalCollection<>(Object.class, true, contents);
  }

  // TODO: use this

       * we're copying into a `contents` array whose type allows it to contain nulls. Still, it's
       * worth noting that we promise not to put nulls into the array in the first `size` elements.
       * We uphold that promise here because our callers promise that `elements` will not contain
       * nulls in its first `n` elements.
       */
      System.arraycopy(elements, 0, contents, size, n);
      size += n;

   *       C}, instance methods are skipped for nulls test.
   *   <li>Nulls test is not performed on method return values unless the method is a visible static
   *       factory method whose return type is {@code C} or {@code C}'s subtype.
   * </ul>
   *
   * <p>In all cases, if {@code C} needs custom logic for testing nulls, you can add an explicit

        return loader.load(key);
      }

      @Override
      public Map<K, V> loadAll(Iterable<? extends K> keys) throws Exception {
        Map<K, V> result = new HashMap<>(); // allow nulls
        for (K key : keys) {
          result.put(key, load(key));
        }
        return result;
      }
    };
  }

   *       C}, instance methods are skipped for nulls test.
   *   <li>Nulls test is not performed on method return values unless the method is a visible static
   *       factory method whose return type is {@code C} or {@code C}'s subtype.
   * </ul>
   *
   * <p>In all cases, if {@code C} needs custom logic for testing nulls, you can add an explicit

import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.List;
import org.jspecify.annotations.Nullable;

/**
 * An ordering that treats all references as equals, even nulls.
 *
 * @author Emily Soldal
 */
@GwtCompatible
final class AllEqualOrdering extends Ordering<@Nullable Object> implements Serializable {
  static final AllEqualOrdering INSTANCE = new AllEqualOrdering();

import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.List;
import org.jspecify.annotations.Nullable;

/**
 * An ordering that treats all references as equals, even nulls.
 *
 * @author Emily Soldal
 */
@GwtCompatible
final class AllEqualOrdering extends Ordering<@Nullable Object> implements Serializable {
  static final AllEqualOrdering INSTANCE = new AllEqualOrdering();

    }

    /**
     * Test getAnchorSet with null input
     */
    @Test
    public void test_getAnchorSet_withNull() {
        FessCrawlerThread crawlerThread = new FessCrawlerThread();

        Set<RequestData> result = crawlerThread.getAnchorSet(null);
        assertNull(result, "getAnchorSet should return null for null input");
    }

    /**
     * Test getAnchorSet with single string