}

  /*
   * To avoid the need to call requireNonNull so much, we could consider more clever approaches,
   * such as:
   *
   * - Make checkOpen return the non-null `seq`. Then callers can assign that to a local variable or
   *   even back to `this.seq`. However, that may suggest that we're defending against concurrent
   *   mutation, which is not an actual risk because we use `synchronized`.

    }

    /** Creates a class loader with the given base URL as its classpath. */
    URLClassLoader newLoader(URL base) {
      // We use the bootstrap class loader as the parent because Finalizer by design uses
      // only standard Java classes. That also means that FinalizableReferenceQueueTest
      // doesn't pick up the wrong version of the Finalizer class.
      return new URLClassLoader(new URL[] {base}, null);
    }

    }

    /** Creates a class loader with the given base URL as its classpath. */
    URLClassLoader newLoader(URL base) {
      // We use the bootstrap class loader as the parent because Finalizer by design uses
      // only standard Java classes. That also means that FinalizableReferenceQueueTest
      // doesn't pick up the wrong version of the Finalizer class.
      return new URLClassLoader(new URL[] {base}, null);
    }

 * create the memory pressure required to cause soft references to be cleared.
 *
 * <p>This class only provides testing utilities. It is not designed for direct use in production or
 * for benchmarking.
 *
 * @author mike nonemacher
 * @author Martin Buchholz
 * @since 11.0
 */
@GwtIncompatible
@J2ktIncompatible
@J2ObjCIncompatible // gc

 *       <i>any</i> eight bits could be consistently used.
 *   <li><b>cryptographic:</b> certain hash functions such as {@link Hashing#sha512} are designed to
 *       make it as infeasible as possible to reverse-engineer the input that produced a given hash
 *       code, or even to discover <i>any</i> two distinct inputs that yield the same result. These

import java.util.concurrent.TimeUnit;

@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
abstract class SmoothRateLimiter extends RateLimiter {
  /*
   * How is the RateLimiter designed, and why?
   *
   * The primary feature of a RateLimiter is its "stable rate", the maximum rate that it should
   * allow in normal conditions. This is enforced by "throttling" incoming requests as needed. For

     * <p>The online hash flooding detecting in RegularSetBuilderImpl.add can detect e.g. many
     * exactly matching hash codes, which would cause construction to take O(n^2), but can't detect
     * e.g. hash codes adversarially designed to go into ascending table locations, which keeps
     * construction O(n) (as desired) but then can have O(n) queries later.
     *
     * <p>If this returns false, then no query can take more than O(log n).
     *

   * or extract a variable, and put the suppression on that. However, a local variable typically
   * doesn't work: Because nullness analyses typically infer the nullness of local variables,
   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the
   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.

                (v1, v2) -> {
                  throw new IllegalArgumentException("Multiple values for key: " + v1 + ", " + v2);
                }),
        (accum, t) -> {
          /*
           * We assign these to variables before calling checkNotNull to work around a bug in our
           * nullness checker.
           */
          K key = keyFunction.apply(t);
          V newValue = valueFunction.apply(t);

4.  Serialized forms of ALL objects are subject to change unless noted
    otherwise. Do not persist these and assume they can be read by a future
    version of the library.

5.  Our classes are not designed to protect against a malicious caller. You
    should not use them for communication between trusted and untrusted code.

6.  For the mainline flavor, we test the libraries using OpenJDK 8, 11, and 17