/** Implementation of an {@link Optional} containing a reference. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Present<T> extends Optional<T> {
  private final T reference;

  Present(T reference) {
    this.reference = reference;
  }

  @Override
  public boolean isPresent() {
    return true;
  }

  @Override
  public T get() {
    return reference;
  }

  @Override

/** Implementation of an {@link Optional} containing a reference. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Present<T> extends Optional<T> {
  private final T reference;

  Present(T reference) {
    this.reference = reference;
  }

  @Override
  public boolean isPresent() {
    return true;
  }

  @Override
  public T get() {
    return reference;
  }

  @Override

25786743
```

For a more detailed SELECT SQL reference, please see [here](https://docs.aws.amazon.com/AmazonS3/latest/dev/s3-glacier-select-sql-reference-select.html)

## 5. Explore Further

- [Use `mc` with MinIO Server](https://min.io/docs/minio/linux/reference/minio-mc.html)
- [Use `mc sql` with MinIO Server](https://min.io/docs/minio/linux/reference/minio-mc/mc-sql.html#command-mc.sql)

/**
 * An immutable object that may contain a non-null reference to another object. Each instance of
 * this type either contains a non-null reference, or contains nothing (in which case we say that
 * the reference is "absent"); it is never said to "contain {@code null}".
 *
 * <p>A non-null {@code Optional<T>} reference can be used as a replacement for a nullable {@code T}

    assertNotNull(sepStopwatchA.get());
    // Clear all references to the Stopwatch and wait for it to be gc'd.
    sepStopwatchA.set(null);
    GcFinalization.awaitClear(sepStopwatchRef.get());
    // Return a weak reference to the parallel ClassLoader. This is the reference that should
    // eventually become clear if there are no other references to the ClassLoader.
    return new WeakReference<ClassLoader>(sepLoader);
  }

    implements FinalizableReference {
  /**
   * Constructs a new finalizable soft reference.
   *
   * @param referent to softly reference
   * @param queue that should finalize the referent
   */
  protected FinalizableSoftReference(@CheckForNull T referent, FinalizableReferenceQueue queue) {
    super(referent, queue.queue);
    queue.cleanUp();
  }

      return created;
    }

    // N.B. Draining the queue is only necessary to ensure that we don't accumulate empty references
    // in the array. We could skip this if we decide we don't care about holding on to Reference
    // objects indefinitely.
    private void drainQueue() {
      Reference<? extends L> ref;
      while ((ref = queue.poll()) != null) {

  private static final double ALLOWED_ERROR = 1.0e-10;
  private static final QuantilesAlgorithm REFERENCE_ALGORITHM = QuantilesAlgorithm.SORTING;
  private static final Set<QuantilesAlgorithm> NON_REFERENCE_ALGORITHMS =
      Sets.difference(
          ImmutableSet.copyOf(QuantilesAlgorithm.values()), ImmutableSet.of(REFERENCE_ALGORITHM));

  private double[] dataset;

  @Override
  protected void setUp() {

    if (adjacentNodes != null) {
      checkState(adjacentNodes.add(node));
    }
  }

  @CheckForNull
  private static <T> T getReference(@CheckForNull Reference<T> reference) {
    return (reference == null) ? null : reference.get();
  }

    }

    @Override
    public void finalizeReferent() {
      finalizeReferentCalled = true;
    }
  }

  /**
   * Keeps a weak reference to the underlying reference queue. When this reference is cleared, we
   * know that the background thread has stopped and released its strong reference.
   */
  private WeakReference<ReferenceQueue<Object>> queueReference;


  public void testThatFinalizerStops() {
    weaklyReferenceQueue();