import java.util.concurrent.Future;
import java.util.concurrent.TimeoutException;

/**
 * Testing utilities relating to garbage collection finalization.
 *
 * <p>Use this class to test code triggered by finalization, that is, one of the following
 * actions taken by the java garbage collection system:
 *
 * <ul>
 *   <li>invoking the {@code finalize} methods of unreachable objects

import java.util.concurrent.Future;
import java.util.concurrent.TimeoutException;

/**
 * Testing utilities relating to garbage collection finalization.
 *
 * <p>Use this class to test code triggered by finalization, that is, one of the following
 * actions taken by the java garbage collection system:
 *
 * <ul>
 *   <li>invoking the {@code finalize} methods of unreachable objects

    Striped<ReadWriteLock> striped = Striped.lazyWeakReadWriteLock(1000);
    Object key = new Object();
    Lock readLock = striped.get(key).readLock();
    WeakReference<Object> garbage = new WeakReference<>(new Object());
    GcFinalization.awaitClear(garbage);
    Lock writeLock = striped.get(key).writeLock();
    readLock.lock();
    assertFalse(writeLock.tryLock());
    readLock.unlock();
  }

  /*
   * The following tests check that the use of FinalizableReferenceQueue does not prevent the
   * ClassLoader that loaded that class from later being garbage-collected. If anything continues
   * to reference the FinalizableReferenceQueue class then its ClassLoader cannot be
   * garbage-collected, even if there are no more instances of FinalizableReferenceQueue itself.

   * it would prevent our class loader from getting garbage collected.
   */
  static class DecoupledLoader implements FinalizerLoader {
    private static final String LOADING_ERROR =
        "Could not load Finalizer in its own class loader. Loading Finalizer in the current class "
            + "loader instead. As a result, you will not be able to garbage collect this class "

   * it would prevent our class loader from getting garbage collected.
   */
  static class DecoupledLoader implements FinalizerLoader {
    private static final String LOADING_ERROR =
        "Could not load Finalizer in its own class loader. Loading Finalizer in the current class "
            + "loader instead. As a result, you will not be able to garbage collect this class "

of Go values and free that space manually all at once, safely. The purpose
of this functionality is to improve efficiency: manually freeing memory
before a garbage collection delays that cycle. Less frequent cycles means
the CPU cost of the garbage collector is incurred less frequently.

This functionality in this package is mostly captured in the Arena type.
Arenas allocate large chunks of memory for Go values, so they're likely to

    Striped<ReadWriteLock> striped = Striped.lazyWeakReadWriteLock(1000);
    Object key = new Object();
    Lock readLock = striped.get(key).readLock();
    WeakReference<Object> garbage = new WeakReference<>(new Object());
    GcFinalization.awaitClear(garbage);
    Lock writeLock = striped.get(key).writeLock();
    readLock.lock();
    assertFalse(writeLock.tryLock());
    readLock.unlock();
  }

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.errorprone.annotations.DoNotMock;

/**
 * Implemented by references that have code to run after garbage collection of their referents.
 *
 * @see FinalizableReferenceQueue
 * @author Bob Lee
 * @since 2.0
 */
@DoNotMock("Use an instance of one of the Finalizable*Reference classes")
@J2ktIncompatible
@GwtIncompatible

 * loader. That way, this class doesn't prevent the main class loader from getting garbage
 * collected, and this class can detect when the main class loader has been garbage collected and
 * stop itself.
 */
// no @ElementTypesAreNonNullByDefault for the reasons discussed above
public class Finalizer implements Runnable {

  private static final Logger logger = Logger.getLogger(Finalizer.class.getName());