* an {@code ArrayTable} concurrently and one of the threads modifies its value, there is no
 * guarantee that the new value will be fully visible to the other threads. To guarantee that
 * modifications are visible, synchronize access to the table. Unlike other {@code Table}
 * implementations, synchronization is unnecessary between a thread that writes to one cell and a
 * thread that reads from another.
 *

   * this fluent iterable contains fewer than {@code numberToSkip} elements, the returned fluent
   * iterable skips all of its elements.
   *
   * <p>Modifications to this fluent iterable before a call to {@code iterator()} are reflected in
   * the returned fluent iterable. That is, the iterator skips the first {@code numberToSkip}

   * elements.length) are all {@code null}.
   */
  @VisibleForTesting transient @Nullable Object @Nullable [] elements;

  /**
   * Keeps track of metadata like the number of hash table bits and modifications of this data
   * structure (to make it possible to throw ConcurrentModificationException in the iterator). Note
   * that we choose not to make this volatile, so we do less of a "best effort" to track such

 * Pat Fisher, Mike Judd.
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/test/tck/JSR166TestCase.java?revision=1.90
 * (We have made some trivial local modifications (commented out
 * uncompilable code).)
 */

package com.google.common.util.concurrent;

import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.TimeUnit.MILLISECONDS;

         * populated.
         */
        result = result.add(requireNonNull(other.dedupedElements[i]));
      }
      return result;
    }

    /**
     * Creates a new copy of this SetBuilderImpl. Modifications to that SetBuilderImpl will not
     * affect this SetBuilderImpl or sets constructed from this SetBuilderImpl via build().
     */
    abstract SetBuilderImpl<E> copy();

    /**

   * {@code iterable} contains fewer than {@code numberToSkip} elements, the returned iterable skips
   * all of its elements.
   *
   * <p>Modifications to the underlying {@link Iterable} before a call to {@code iterator()} are
   * reflected in the returned iterator. That is, the iterator skips the first {@code numberToSkip}

   * allocated, the value of {@code metadata} combines the number of bits in the "short hash", in
   * its bottom {@value CompactHashing#HASH_TABLE_BITS_MAX_BITS} bits, with a modification count in
   * the remaining bits that is used to detect concurrent modification during iteration.
   */
  private transient int metadata;

  /** The number of elements contained in the set. */
  private transient int size;

   * {@code k} to {@code function.apply(k)}. The {@code keySet}, {@code values}, and {@code
   * entrySet} views of the returned map iterate in the same order as the backing set.
   *
   * <p>Modifications to the backing set are read through to the returned map. The returned map
   * supports removal operations if the backing set does. Removal operations write through to the

   * {@code k} to {@code function.apply(k)}. The {@code keySet}, {@code values}, and {@code
   * entrySet} views of the returned map iterate in the same order as the backing set.
   *
   * <p>Modifications to the backing set are read through to the returned map. The returned map
   * supports removal operations if the backing set does. Removal operations write through to the

    mod.put(4, "four");
    assertEquals(true, unmod.get(4).equals("four"));
    assertEquals(true, unmod.inverse().get("four").equals(4));

    /* UnsupportedOperationException on direct modifications. */
    assertThrows(UnsupportedOperationException.class, () -> unmod.put(4, "four"));
    assertThrows(UnsupportedOperationException.class, () -> unmod.forcePut(4, "four"));