@Override
  @CheckForNull
  public abstract V get(@CheckForNull Object key);

  /**
   * {@inheritDoc}
   *
   * <p>See <a
   * href="https://developer.android.com/reference/java/util/Map.html#getOrDefault%28java.lang.Object,%20V%29">{@code
   * Map.getOrDefault}</a>.
   *
   * @since 23.5 (but since 21.0 in the JRE <a
   *     href="https://github.com/google/guava#guava-google-core-libraries-for-java">flavor</a>).

   * different input keys. This test verifies that each possible 1-bit key delta achieves avalanche.
   *
   * <p>For more information: http://burtleburtle.net/bob/hash/avalanche.html
   */
  static void checkAvalanche(HashFunction function, int trials, double epsilon) {
    Random rand = new Random(0);
    int keyBits = 32;
    int hashBits = function.bits();

 * find it easier to use a framework. Frameworks automate the process, often adding features like
 * monitoring, debugging, and cancellation. Examples of frameworks include:
 *
 * <ul>
 *   <li><a href="https://dagger.dev/producers.html">Dagger Producers</a>
 * </ul>
 *
 * <p>If you do chain your operations manually, you may want to use {@link FluentFuture}.
 *
 * @author Kevin Bourrillion
 * @author Nishant Thakkar
 * @author Sven Mawson

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Static convenience methods that serve the same purpose as Java language <a
 * href="https://docs.oracle.com/javase/8/docs/technotes/guides/language/assert.html">assertions</a>,
 * except that they are always enabled. These methods should be used instead of Java assertions
 * whenever there is a chance the check may fail "in real life". Example:
 *
 * <pre>{@code

  public static final MediaType XHTML_UTF_8 = createConstantUtf8(APPLICATION_TYPE, "xhtml+xml");

  /**
   * Extensible Resource Descriptors. This is not yet registered with the IANA, but it is specified
   * by OASIS in the <a href="http://docs.oasis-open.org/xri/xrd/v1.0/cd02/xrd-1.0-cd02.html">XRD
   * definition</a> and implemented in projects such as <a

 * {@linkplain #close closed}. This is intended to approximately emulate the behavior of Java 7's <a
 * href="http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html"
 * >try-with-resources</a> statement in JDK6-compatible code. Running on Java 7, code using this
 * should be approximately equivalent in behavior to the same code written with try-with-resources.

            <charset>UTF-8</charset>
            <additionalOptions>
              <additionalOption>-XDignore.symbol.file</additionalOption>
              <additionalOption>-Xdoclint:-html</additionalOption>
            </additionalOptions>
            <linksource>true</linksource>
            <source>${java.specification.version}</source>

   *   <li>Underscores ('_') are permitted wherever dashes ('-') are permitted.
   *   <li>Parts other than the final part may start with a digit, as mandated by <a
   *       href="https://tools.ietf.org/html/rfc1123#section-2">RFC 1123</a>.
   * </ul>
   *
   * @param domain A domain name (not IP address)
   * @throws IllegalArgumentException if {@code domain} is not syntactically valid according to
   *     {@link #isValid}

 * assigned characters, including important CJK characters and emoji.
 *
 * <p>Supplementary characters are <a
 * href="https://docs.oracle.com/javase/8/docs/api/java/lang/Character.html#supplementary">encoded
 * into a {@code String} using surrogate pairs</a>, and a {@code CharMatcher} treats these just as
 * two separate characters. {@link #countIn} counts each supplementary character as 2 {@code char}s.
 *

 * powerful advantage. Although Java offers certain immutable collection factory methods, such as
 * {@link Collections#singleton(Object)} and <a
 * href="https://docs.oracle.com/javase/9/docs/api/java/util/Set.html#immutable">{@code Set.of}</a>,
 * we recommend using <i>these</i> classes instead for this reason (as well as for consistency).
 *
 * <h4>Creation</h4>
 *