* Nearly all declarations in this class are package-private,
   * accessed directly by subclasses.
   *
   * Table entries are of class Cell; a variant of AtomicLong padded
   * to reduce cache contention on most processors. Padding is
   * overkill for most Atomics because they are usually irregularly
   * scattered in memory and thus don't interfere much with each
   * other. But Atomic objects residing in arrays will tend to be

            Collections.singletonList("A"),
            ImmutableList.of("A"),
            ImmutableList.of("A", "A", "B", "C"),
            ImmutableList.of("A", "A", "D", "E", "B", "C"));

    String format = "Adding %s at %s";
    for (int i = 0; i < toAdd.size(); i++) {
      int index = indexes.get(i);
      Iterable<String> iterableToAdd = toAdd.get(i);
      boolean expectedChanged = iterableToAdd.iterator().hasNext();

    putEdge(5, 1);
    putEdge(1, 2);
    putEdge(3, 1);
  }

  // Element Mutation

  @Test
  public void putEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future
    // modifications to proxy methods)
    addNode(N1);
    addNode(N2);

    assertThat(graphAsMutableGraph.putEdge(N1, N2)).isTrue();
  }

    }
    assertWithMessage("table size after adding " + size + " elements")
        .that(bucketsOf(map1))
        .isEqualTo(initialBuckets);

    /*
     * Something slightly different happens when the entries are added all at
     * once; make sure that passes too.
     */
    map2.putAll(map1);
    assertWithMessage("table size after adding " + size + " elements")
        .that(bucketsOf(map1))

    }
    assertWithMessage("table size after adding " + size + " elements")
        .that(bucketsOf(map1))
        .isEqualTo(initialBuckets);

    /*
     * Something slightly different happens when the entries are added all at
     * once; make sure that passes too.
     */
    map2.putAll(map1);
    assertWithMessage("table size after adding " + size + " elements")
        .that(bucketsOf(map1))

      }
      return false;
    }

    /**
     * Returns a string in the format specified by {@link MoreObjects#toStringHelper(Object)}.
     *
     * <p>After calling this method, you can keep adding more properties to later call toString()
     * again and get a more complete representation of the same object; but properties cannot be
     * removed, so this only allows limited reuse of the helper instance. The helper allows

            return 0;
          }
        } else {
          checkArgument(
              occurrences <= Integer.MAX_VALUE - current,
              "Overflow adding %s occurrences to a count of %s",
              occurrences,
              current);
          int next = current + occurrences;
          if (countMap.replace(element, current, next)) {
            return current;

 * replace an existing pair with the same key and value, if such a pair is present. With collections
 * like {@link List} that allow duplicates, the collection will keep the existing key-value pairs
 * while adding a new pair.
 *
 * <p>This class is not threadsafe when any concurrent operations update the multimap, even if the
 * underlying map and {@link #createCollection()} method return threadsafe classes. Concurrent read

 *
 * @author Mike Bostock
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
/*
 * I have decided not to bother adding @ParametricNullness annotations in this class. Adding them is
 * a lot of busy work, and the annotation matters only when the APIs to be annotated are visible to
 * Kotlin code. In this class, nothing is publicly visible (nor exposed indirectly through a

              return oldValue;
            }
          } catch (ArithmeticException overflow) {
            throw new IllegalArgumentException(
                "Overflow adding " + occurrences + " occurrences to a count of " + oldValue);
          }
        } else {
          // In the case of a concurrent remove, we might observe a zero value, which means another