* arrays. Like {@code Joiner}, it is thread-safe and immutable.
   *
   * <p>In addition to operating on {@code Map} instances, {@code MapJoiner} can operate on {@code
   * Multimap} entries in two distinct modes:
   *
   * <ul>
   *   <li>To output a separate entry for each key-value pair, pass {@code multimap.entries()} to a

 *   <li>{@link Charsets#US_ASCII} specifies the {@code Charset} of ASCII characters.
 *   <li>{@link CharMatcher#ascii} matches ASCII characters and provides text processing methods
 *       which operate only on the ASCII characters of a string.
 * </ul>
 *
 * @author Catherine Berry
 * @author Gregory Kick
 * @since 7.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Ascii {

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An assortment of mainly legacy static utility methods that operate on or return objects of type
 * {@code Iterable}. Except as noted, each method has a corresponding {@link Iterator}-based method
 * in the {@link Iterators} class.
 *

    z += shiftMix(v[1]) * K1;
    x = rotateRight(z + x, 39) * K1;
    y = rotateRight(y, 33) * K1;

    // Decrease length to the nearest multiple of 64, and operate on 64-byte chunks.
    length = (length - 1) & ~63;
    do {
      x = rotateRight(x + y + v[0] + load64(bytes, offset + 16), 37) * K1;
      y = rotateRight(y + v[1] + load64(bytes, offset + 48), 42) * K1;

import java.util.Collection;
import java.util.Map;
import java.util.OptionalDouble;
import java.util.OptionalInt;
import java.util.OptionalLong;
import javax.annotation.CheckForNull;

/**
 * Helper functions that operate on any {@code Object}, and are not already provided in {@link
 * java.util.Objects}.
 *
 * <p>See the Guava User Guide on <a
 * href="https://github.com/google/guava/wiki/CommonObjectUtilitiesExplained">writing {@code Object}

        existingCounter = countMap.putIfAbsent(element, new AtomicInteger(occurrences));
        if (existingCounter == null) {
          return 0;
        }
        // existingCounter != null: fall through to operate against the existing AtomicInteger
      }

      while (true) {
        int oldValue = existingCounter.get();
        if (oldValue != 0) {
          try {

   *
   * <pre>{@code
   * for (B b0 : lists.get(0)) {
   *   for (B b1 : lists.get(1)) {
   *     ...
   *     ImmutableList<B> tuple = ImmutableList.of(b0, b1, ...);
   *     // operate on tuple
   *   }
   * }
   * }</pre>
   *
   * <p>Note that if any input list is empty, the Cartesian product will also be empty. If no lists

 */

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import junit.framework.TestCase;

/**
 * Unit tests for {@link Runnables}.
 *
 * @author Olivier Pernet
 */
@GwtCompatible
public class RunnablesTest extends TestCase {
  public void testDoNothingRunnableIsSingleton() {
    assertSame(Runnables.doNothing(), Runnables.doNothing());
  }

import com.google.common.annotations.GwtCompatible;
import java.util.Arrays;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Helper functions that can operate on any {@code Object}.
 *
 * <p>See the Guava User Guide on <a
 * href="https://github.com/google/guava/wiki/CommonObjectUtilitiesExplained">writing {@code Object}
 * methods with {@code Objects}</a>.
 *

  /**
   * Returns all nodes in this graph adjacent to {@code node} which can be reached by traversing
   * {@code node}'s incoming edges <i>against</i> the direction (if any) of the edge.
   *
   * <p>Some algorithms that operate on a {@code PredecessorsFunction} may produce undesired results
   * if the returned {@link Iterable} contains duplicate elements. Implementations of such
   * algorithms should document their behavior in the presence of duplicates.