if (threadStarted) {
      return;
    }

    Reference<?> reference;
    while ((reference = queue.poll()) != null) {
      /*
       * This is for the benefit of phantom references. Weak and soft references will have already
       * been cleared by this point.
       */
      reference.clear();
      try {
        ((FinalizableReference) reference).finalizeReferent();
      } catch (Throwable t) {

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

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

  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>cyclic-reference</groupId>
    <artifactId>parent</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>
  <artifactId>module-a</artifactId>

  <dependencies>
    <dependency>
      <groupId>cyclic-reference</groupId>
      <artifactId>module-b</artifactId>
      <version>1.0-SNAPSHOT</version>
    </dependency>

@J2ktIncompatible
@GwtIncompatible
public abstract class FinalizableWeakReference<T> extends WeakReference<T>
    implements FinalizableReference {
  /**
   * Constructs a new finalizable weak reference.
   *
   * @param referent to weakly reference
   * @param queue that should finalize the referent
   */
  protected FinalizableWeakReference(@Nullable T referent, FinalizableReferenceQueue queue) {
    super(referent, queue.queue);

    schemas: Optional[dict[str, Union[Schema, Reference]]] = None
    responses: Optional[dict[str, Union[Response, Reference]]] = None
    parameters: Optional[dict[str, Union[Parameter, Reference]]] = None
    examples: Optional[dict[str, Union[Example, Reference]]] = None
    requestBodies: Optional[dict[str, Union[RequestBody, Reference]]] = None
    headers: Optional[dict[str, Union[Header, Reference]]] = None

	relations := []Relation{
		{
			Name: "Account", Type: schema.HasOne, Schema: "User", FieldSchema: "Account",
			References: []Reference{{"ID", "User", "UserID", "Account", "", true}},
		},
		{
			Name: "Pets", Type: schema.HasMany, Schema: "User", FieldSchema: "Pet",
			References: []Reference{{"ID", "User", "UserID", "Pet", "", true}},
		},
		{
			Name: "Toys", Type: schema.HasMany, Schema: "User", FieldSchema: "Toy",

#   request - Cache only for current request + its child requests
#   none    - Disable caching entirely
#
# REFERENCE OPTIONS:
#   hard - Strong reference (stays in memory, faster access)
#   soft - Weak reference (can be garbage collected under memory pressure)
#
# CONFIGURATION BREAKDOWN:

func (set TargetIDSet) Union(sset TargetIDSet) TargetIDSet {
	nset := set.Clone()

	for k := range sset {
		nset.add(k)
	}

	return nset
}

// Difference - returns difference with given set as new set.
func (set TargetIDSet) Difference(sset TargetIDSet) TargetIDSet {
	nset := NewTargetIDSet()
	for k := range set {
		if _, ok := sset[k]; !ok {
			nset.add(k)
		}
	}

	return nset
}

        () -> equalsTester.addEqualityGroup(reference, equalObject1, null));
  }

  /** Test adding null equal object yields error */
  public void testAddNullEqualObject() {
    assertThrows(
        NullPointerException.class,
        () -> equalsTester.addEqualityGroup(reference, (Object[]) null));
  }

  /**
   * Test adding objects only by addEqualityGroup, with no reference object specified in the
   * constructor.
   */

   * ObjectArrays, which is the main caller of this method.)
   */
  static <T extends @Nullable Object> T[] newArray(T[] reference, int length) {
    T[] empty = reference.length == 0 ? reference : Arrays.copyOf(reference, 0);
    return Arrays.copyOf(empty, length);
  }

  /** Equivalent to Arrays.copyOfRange(source, from, to, arrayOfType.getClass()). */
  /*