for use on Android or by any library that wants to be compatible with Android.
These flavors are specified in the Maven version field as either `33.2.0-jre` or
`33.2.0-android`. For more about depending on Guava, see
[using Guava in your build].

To add a dependency on Guava using Maven, use the following:

```xml
<dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>

  /**
   * Returns an unmodifiable iterable over the nodes in a tree structure, using pre-order traversal.
   * That is, each node's subtrees are traversed after the node itself is returned.
   *
   * <p>No guarantees are made about the behavior of the traversal when nodes change while iteration
   * is in progress or when the iterators generated by {@link #children} are advanced.
   *

     */
    /*
     * TODO(cpovirk): use Object[] instead of E[] in the mainline? (The backport is different and
     * doesn't need this suppression, but we keep it to minimize diffs.) Generally be more clear
     * about when we have an Object[] vs. a Comparable[] or other array type in internalArray? If we
     * used Object[], we might be able to optimize toArray() to use clone() sometimes. (See
     * cl/592273615 and cl/592273683.)
     */

      Multiset<?> multisetToModify, Multiset<?> multisetToRetain) {
    return retainOccurrencesImpl(multisetToModify, multisetToRetain);
  }

  /** Delegate implementation which cares about the element type. */
  private static <E extends @Nullable Object> boolean retainOccurrencesImpl(
      Multiset<E> multisetToModify, Multiset<?> occurrencesToRetain) {
    checkNotNull(multisetToModify);

   * value should be required because the instance is known to be present, use {@link #get()}
   * instead. For a default value of {@code null}, use {@link #orNull}.
   *
   * <p>Note about generics: The signature {@code public T or(T defaultValue)} is overly
   * restrictive. However, the ideal signature, {@code public <S super T> S or(S)}, is not legal

  @J2ktIncompatible
  @GwtIncompatible // suite
  public static Test suite() {
    TestSuite suite = new TestSuite();
    // TODO(lowasser): should we force TreeMultimap to be more thorough about checking nulls?
    suite.addTest(
        SortedSetMultimapTestSuiteBuilder.using(
                new TestStringSetMultimapGenerator() {
                  @Override

     *
     * <p>For users of the {@code -jre} flavor of Guava, the object can be any {@code
     * AutoCloseable}. For users of the {@code -android} flavor, the object must be a {@code
     * Closeable}. (For more about the flavors, see <a
     * href="https://github.com/google/guava#adding-guava-to-your-build">Adding Guava to your
     * build</a>.)
     *

   *       threads, RPC network threads, or other latency-sensitive threads. In those cases, slow
   *       listeners can harm responsiveness, slow the system as a whole, or worse. (See also the
   *       note about locking below.)
   *   <li>If many tasks will be triggered by the same event, one heavyweight task may delay other
   *       tasks -- even tasks that are not themselves {@code directExecutor} tasks.

  @J2ktIncompatible
  @GwtIncompatible // suite
  public static Test suite() {
    TestSuite suite = new TestSuite();
    // TODO(lowasser): should we force TreeMultimap to be more thorough about checking nulls?
    suite.addTest(
        SortedSetMultimapTestSuiteBuilder.using(
                new TestStringSetMultimapGenerator() {
                  @Override

  //    the initial write (just stronger guarantees if it does).
  //
  // See: http://cs.oswego.edu/pipermail/concurrency-interest/2015-January/013800.html
  // For a (long) discussion about this specific issue and the general futility of life.
  //
  // For the time being we are OK with the problem discussed above since it requires a caller to