* is the only one in use, but if we encounter nested concatenations, we start a deque of
     * meta-iterators rather than letting the nesting get arbitrarily deep.  This keeps each
     * operation O(1).
     */

    private @Nullable Iterator<? extends Iterator<? extends T>> topMetaIterator;

    // Only becomes nonnull if we encounter nested concatenations.

                sb.append("]");
            }
            sb.append("; ");
            target = target.getCause();
            if (target != null) {
                sb.append("nested: ");
            }
        }
        return sb.toString();
    }

    /**
     * Processes a label request.
     * @param request The HTTP request.
     * @param response The HTTP response.

* kubectl now supports validation of nested objects with different ApiGroups (e.g. objects in a List) ([#25172](https://github.com/kubernetes/kubernetes/pull/25172), [@pwittrock](https://github.com/pwittrock))

   * elements without resizing. Note that this is not what {@link HashSet#HashSet(int)} does, but it
   * is what most users want and expect it to do.
   *
   * <p>This behavior can't be broadly guaranteed, but has been tested with OpenJDK 1.7 and 1.8.
   *
   * @param expectedSize the number of elements you expect to add to the returned set
   * @return a new, empty hash set with enough capacity to hold {@code expectedSize} elements

    }
  }

  // Non-static factory implementation classes

  /** Implementation of {@link #negate()}. */
  private static class Negated extends CharMatcher {

    final CharMatcher original;

    Negated(CharMatcher original) {
      this.original = checkNotNull(original);
    }

    @Override
    public boolean matches(char c) {
      return !original.matches(c);

   * <p>The function is applied lazily, invoked when needed. This is necessary for the returned
   * multimap to be a view, but it means that the function will be applied many times for bulk
   * operations like {@link Multimap#containsValue} and {@code Multimap.toString()}. For this to
   * perform well, {@code function} should be fast. To avoid lazy evaluation when the returned

   * <p>The function is applied lazily, invoked when needed. This is necessary for the returned
   * multimap to be a view, but it means that the function will be applied many times for bulk
   * operations like {@link Multimap#containsValue} and {@code Multimap.toString()}. For this to
   * perform well, {@code function} should be fast. To avoid lazy evaluation when the returned

    assertFalse(changed);
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointerExceptions() {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(Iterators.class);
  }

  @GwtIncompatible // Only used by @GwtIncompatible code
  private abstract static class EmptyIteratorTester extends IteratorTester<Integer> {

 * characters that need to be encoded is different for each component. For example, the path
 * component must escape all of its `?` characters, otherwise it could be interpreted as the
 * start of the URL's query. But within the query and fragment components, the `?` character
 * doesn't delimit anything and doesn't need to be escaped.
 *
 * ```java

 *
 * <h3>Performance</h3>
 *
 * <p>Avoid passing message arguments that are expensive to compute; your code will always compute
 * them, even though they usually won't be needed. If you have such arguments, use the conventional
 * if/throw idiom instead.
 *
 * <p>Depending on your message arguments, memory may be allocated for boxing and varargs array