import java.util.List;
import java.util.Set;
import org.jspecify.annotations.NullMarked;

/**
 * Create string sets for collection tests.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public abstract class TestStringSetGenerator implements TestSetGenerator<String> {
  @Override
  public SampleElements<String> samples() {
    return new Strings();
  }

  @Override
  public Set<String> create(Object... elements) {

import org.jspecify.annotations.Nullable;

/**
 * An abstract {@code ScheduledExecutorService} that allows subclasses to {@linkplain
 * #wrapTask(Callable) wrap} tasks before they are submitted to the underlying executor.
 *
 * <p>Note that task wrapping may occur even if the task is never executed.
 *
 * @author Luke Sandberg
 */
@J2ktIncompatible
@GwtIncompatible

 *
 * @author Isaac Shum
 * @since 10.0
 */
@J2ktIncompatible
@GwtIncompatible
public abstract class ForwardingListeningExecutorService extends ForwardingExecutorService
    implements ListeningExecutorService {
  /** Constructor for use by subclasses. */
  protected ForwardingListeningExecutorService() {}

  @Override
  protected abstract ListeningExecutorService delegate();

  @Override

import jcifs.dcerpc.ndr.NdrException;

/**
 * Base class for SMB Witness Protocol RPC messages as defined in MS-SWN specification.
 * This class extends DcerpcMessage to provide witness-specific RPC operations.
 */
public abstract class WitnessRpcMessage extends DcerpcMessage {

    // MS-SWN Witness Protocol Interface UUID and Version
    /** Witness Protocol Interface UUID from MS-SWN specification */

import org.jspecify.annotations.NullMarked;

/**
 * Implementation helper for {@link TestMapGenerator} for use with enum maps.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public abstract class TestEnumMapGenerator implements TestMapGenerator<AnEnum, String> {

  @Override
  public SampleElements<Entry<AnEnum, String>> samples() {
    return new SampleElements<>(
        mapEntry(AnEnum.A, "January"),

 * reasons).
 */
@GwtCompatible
abstract class AbstractIterator<T extends @Nullable Object> implements Iterator<T> {
  private State state = State.NOT_READY;

  protected AbstractIterator() {}

  private enum State {
    READY,
    NOT_READY,
    DONE,
    FAILED,
  }

  private @Nullable T next;

  protected abstract @Nullable T computeNext();

  @CanIgnoreReturnValue

 * @since 3.0
 */
@GwtCompatible
public abstract class ForwardingSortedSetMultimap<
        K extends @Nullable Object, V extends @Nullable Object>
    extends ForwardingSetMultimap<K, V> implements SortedSetMultimap<K, V> {

  /** Constructor for use by subclasses. */
  protected ForwardingSortedSetMultimap() {}

  @Override
  protected abstract SortedSetMultimap<K, V> delegate();

  @Override

import org.jspecify.annotations.Nullable;

/**
 * GWT emulated version of {@link ImmutableList}. TODO(cpovirk): more doc
 *
 * @author Hayward Chan
 */
abstract class ForwardingImmutableList<E> extends ImmutableList<E> {

  ForwardingImmutableList() {}

  abstract List<E> delegateList();

  @Override
  public int indexOf(@Nullable Object object) {
    return delegateList().indexOf(object);
  }

  @Override

/**
 * An implementation of {@link ImmutableTable} holding an arbitrary number of cells.
 *
 * @author Gregory Kick
 */
@GwtCompatible
abstract class RegularImmutableTable<R, C, V> extends ImmutableTable<R, C, V> {
  RegularImmutableTable() {}

  abstract Cell<R, C, V> getCell(int iterationIndex);

  @Override
  final ImmutableSet<Cell<R, C, V>> createCellSet() {

import org.lastaflute.job.LaJobRuntime;

/**
 * Abstract base class for executable jobs in the Fess search engine.
 * This class provides common functionality for job execution including process management,
 * logging configuration, JVM options, and timeout handling.
 *
 * <p>Subclasses must implement the abstract methods to define specific job behavior
 * and execution type identification.</p>
 *