return (Class<? extends T>) implementations.get(type);
  }

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

  /**
   * Returns an arbitrary instance for {@code type}, or {@code null} if no arbitrary instance can be
   * determined.
   */
  public static <T> @Nullable T get(Class<T> type) {
    T defaultValue = DEFAULTS.getInstance(type);
    if (defaultValue != null) {

   */
  abstract void afterRanInterruptiblyFailure(Throwable error);

  /**
   * Interrupts the running task. Because this internally calls {@link Thread#interrupt()} which can
   * in turn invoke arbitrary code it is not safe to call while holding a lock.
   */
  @SuppressWarnings("Interruption") // We are implementing a user-requested interrupt.
  final void interruptTask() {

      return method.invoke(delegate, args);
    }

    @Override
    public String toString() {
      return "some arbitrary string";
    }
  }

  private static class DelegatingInvocationHandlerWithEquals extends DelegatingInvocationHandler {

    DelegatingInvocationHandlerWithEquals(Object delegate) {
      super(delegate);

  /**
   * Throws {@code t} as if it were an unchecked {@link Throwable}.
   *
   * <p>This method is useful primarily when we make a reflective call to a method with no {@code
   * throws} clause: Java forces us to handle an arbitrary {@link Throwable} from that method,
   * rather than just the {@link RuntimeException} or {@link Error} that should be possible. (And in
   * fact the static type of {@link Throwable} is occasionally justified even for a method with no

  /**
   * Throws {@code t} as if it were an unchecked {@link Throwable}.
   *
   * <p>This method is useful primarily when we make a reflective call to a method with no {@code
   * throws} clause: Java forces us to handle an arbitrary {@link Throwable} from that method,
   * rather than just the {@link RuntimeException} or {@link Error} that should be possible. (And in
   * fact the static type of {@link Throwable} is occasionally justified even for a method with no

    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe
    T arbitrary = (T) ArbitraryInstances.get(type.getRawType());
    if (arbitrary != null) {
      return arbitrary;
    }
    if (type.getRawType() == Class.class) {
      // If parameter is Class<? extends Foo>, we return Foo.class

import com.google.common.collect.testing.SampleElements.Strings;
import java.util.Collection;
import java.util.List;
import org.jspecify.annotations.NullMarked;

/**
 * String creation for testing arbitrary collections.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public abstract class TestStringCollectionGenerator implements TestCollectionGenerator<String> {
  @Override

 */

package com.google.common.base;

import com.google.common.annotations.GwtCompatible;

/**
 * A time source; returns a time value representing the number of nanoseconds elapsed since some
 * fixed but arbitrary point in time. Note that most users should use {@link Stopwatch} instead of
 * interacting with this class directly.
 *
 * <p><b>Warning:</b> this interface can only be used to measure elapsed time, not wall time.
 *

        return ImmutableSet.of(getOnlyElement(set));
      default:
        return new ImmutableEnumSet<>(set);
    }
  }

  /*
   * Notes on EnumSet and <E extends Enum<E>>:
   *
   * This class isn't an arbitrary ForwardingImmutableSet because we need to
   * know that calling {@code clone()} during deserialization will return an
   * object that no one else has a reference to, allowing us to guarantee

  /**
   * Throws {@code t} as if it were an unchecked {@link Throwable}.
   *
   * <p>This method is useful primarily when we make a reflective call to a method with no {@code
   * throws} clause: Java forces us to handle an arbitrary {@link Throwable} from that method,
   * rather than just the {@link RuntimeException} or {@link Error} that should be possible. (And in
   * fact the static type of {@link Throwable} is occasionally justified even for a method with no