![Events Diagram](../assets/images/******@****.***)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java
class PrintingEventListener extends EventListener {

 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public abstract class TestStringCollectionGenerator implements TestCollectionGenerator<String> {
  @Override
  public SampleElements<String> samples() {
    return new Strings();
  }

  @Override
  public Collection<String> create(Object... elements) {
    String[] array = new String[elements.length];
    int i = 0;
    for (Object e : elements) {

public class AllocationBenchmark {
    // Do NOT make any field final (even if it is not annotated with @Param)! See also
    // http://hg.openjdk.java.net/code-tools/jmh/file/tip/jmh-samples/src/main/java/org/openjdk/jmh/samples/JMHSample_10_ConstantFold.java

    // we cannot use individual @Params as some will lead to invalid combinations which do not let the benchmark terminate. JMH offers no

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

/**
 * A generator using sample elements whose hash codes all collide badly.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public abstract class TestCollidingSetGenerator implements TestSetGenerator<Object> {
  @Override
  public SampleElements<Object> samples() {
    return new Colliders();
  }

  @Override

    SortedMultiset<E> emptyMultiset = (SortedMultiset<E>) delegate.create();
    Comparator<? super E> comparator = emptyMultiset.comparator();
    SampleElements<E> samples = delegate.samples();
    List<E> samplesList =
        asList(samples.e0(), samples.e1(), samples.e2(), samples.e3(), samples.e4());

    sort(samplesList, comparator);
    E firstInclusive = samplesList.get(0);
    E lastInclusive = samplesList.get(samplesList.size() - 1);

    private ReserializedCollectionGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen) {
      this.gen = gen;
    }

    @Override
    public SampleElements<E> samples() {
      return gen.samples();
    }

    @Override
    public Collection<E> create(Object... elements) {
      return SerializableTester.reserialize(gen.create(elements));
    }

    @Override

    private ReserializedSetGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen) {
      this.gen = gen;
    }

    @Override
    public SampleElements<E> samples() {
      return gen.samples();
    }

    @Override
    public Set<E> create(Object... elements) {
      return (Set<E>) SerializableTester.reserialize(gen.create(elements));
    }

    @Override

/**
 * Creates collections containing unhashable sample elements, to be tested.
 *
 * @author Regina O'Dell
 */
@GwtCompatible
@NullMarked
public abstract class TestUnhashableCollectionGenerator<T extends Collection<UnhashableObject>>
    implements TestCollectionGenerator<UnhashableObject> {
  @Override
  public SampleElements<UnhashableObject> samples() {
    return new Unhashables();
  }

  @Override

    private ReserializedCollectionGenerator(OneSizeTestContainerGenerator<Collection<E>, E> gen) {
      this.gen = gen;
    }

    @Override
    public SampleElements<E> samples() {
      return gen.samples();
    }

    @Override
    public Collection<E> create(Object... elements) {
      return SerializableTester.reserialize(gen.create(elements));
    }

    @Override

      return (T) in.readObject();
    } catch (IOException | ClassNotFoundException e) {
      throw new AssertionError(e);
    }
  }

  @Override
  public SampleElements<E> samples() {
    return delegate.samples();
  }

  @Override
  public E[] createArray(int length) {
    return delegate.createArray(length);
  }

  @Override
  public Iterable<E> order(List<E> insertionOrder) {