///

## Reduce duplication { #reduce-duplication }

Reducing code duplication is one of the core ideas in **FastAPI**.

As code duplication increments the chances of bugs, security issues, code desynchronization issues (when you update in one place but not in the others), etc.

And these models are all sharing a lot of the data and duplicating attribute names and types.

      if (currentSubscribers == null || !currentSubscribers.removeAll(listenerMethodsForType)) {
        // if removeAll returns true, all we really know is that at least one subscriber was
        // removed... however, barring something very strange we can assume that if at least one
        // subscriber was removed, all subscribers on listener for that event type were... after

    }

    @Test
    void testPerLookupInstantiation() throws Exception {
        String protocol = "perlookup";

        Wagon one = wagonManager.getWagon(protocol);
        Wagon two = wagonManager.getWagon(protocol);

        assertNotSame(one, two);
    }

    private void assertWagon(String protocol) throws Exception {
        Wagon wagon = wagonManager.getWagon(protocol);

 *   <li>Lifecycle management using {@code @PostConstruct} and {@code @PreDestroy} annotations</li>
 * </ul>
 *
 * <p>Components can be registered in two ways:
 * <ul>
 *   <li>As singletons, where one instance is shared throughout the container's lifecycle</li>
 *   <li>As prototypes, where a new instance is created each time the component is requested</li>
 * </ul>
 *

 * allowed to be reclaimed if nobody is holding on to them. This is useful, for example, if one
 * wants to create a {@code Striped<Lock>} of many locks, but worries that in most cases only a
 * small portion of these would be in use.
 *
 * <p>Prior to this class, one might be tempted to use {@code Map<K, Lock>}, where {@code K}

  //      since, after all, this class is also a reentrant mutual exclusion lock!?

  /*
   * One of the key challenges of this class is to prevent lost signals, while trying hard to
   * minimize unnecessary signals. One simple and correct algorithm is to signal some other waiter
   * with a satisfied guard (if one exists) whenever any thread occupying the monitor exits the

 * token68:
 *
 * ```
 * WWW-Authenticate: Digest foo=bar
 * WWW-Authenticate: Digest foo=
 * ```
 *
 * Similarly, the first line has one challenge and the second line has two challenges:
 *
 * ```
 * WWW-Authenticate: Digest ,foo=bar
 * WWW-Authenticate: Digest ,foo
 * ```
 */
fun Headers.parseChallenges(headerName: String): List<Challenge> {

    int initialSize = collection.size();
    assertTrue("remove(present) should return true", collection.remove(e0()));
    assertEquals(
        "remove(present) should decrease a collection's size by one.",
        initialSize - 1,
        collection.size());
    expectMissing(e0());
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, FAILS_FAST_ON_CONCURRENT_MODIFICATION})
  @CollectionSize.Require(SEVERAL)

carefully. Because of this, if you're interested in seeing a new feature in
Guava, the best approach is to create an [issue][] (or comment on an existing
issue if there is one) requesting the feature and describing specific use cases
for it.

If the feature has merit, it will go through a thorough process of API design
and review. Any code should come after this.

 *
 * @author Ben Yu
 */
@NullUnmarked
public class AbstractInvocationHandlerTest extends TestCase {

  private static final ImmutableList<String> LIST1 = ImmutableList.of("one", "two");
  private static final ImmutableList<String> LIST2 = ImmutableList.of("three");

  public void testDelegate() {
    assertEquals(LIST1, ImmutableList.copyOf(newDelegatingList(LIST1)));