// Prefer the heavier "MapRetrievalCache" for nodes if lookup is expensive.
    this.nodeConnections =
        (nodeConnections instanceof TreeMap)
            ? new MapRetrievalCache<N, GraphConnections<N, V>>(nodeConnections)
            : new MapIteratorCache<N, GraphConnections<N, V>>(nodeConnections);
    this.edgeCount = checkNonNegative(edgeCount);
  }

  @Override
  public Set<N> nodes() {

     * @param supplier the supplier will compute the new value
     * @return the session data associated with the key
     */
    @Nullable
    <T> T computeIfAbsent(@Nonnull Key<T> key, @Nonnull Supplier<T> supplier);

    /**
     * Create a key using the given class as an identifier and as the type of the object.
     */
    static <T> Key<T> key(Class<T> clazz) {
        return new Key<>(clazz, clazz);
    }

    /**

    return CompactHashSet.create();
  }

  /**
   * Returns a new array of the given length with the same type as a reference array.
   *
   * @param reference any array of the desired type
   * @param length the length of the new array
   */
  /*
   * The new array contains nulls, even if the old array did not. If we wanted to be accurate, we

    LockingThread thread = new LockingThread(lockA);
    thread.start();

    thread.waitUntilHoldingLock();
    assertFalse(lockA.tryLock());

    thread.releaseLockAndFinish();
    assertTrue(lockA.tryLock());
  }

  public void testReentrantWriteLock_tryLock() throws Exception {
    LockingThread thread = new LockingThread(writeLockA);
    thread.start();

		return errors.New("username and password must be specified as a pair")
	}

	if n.Streaming.Enable {
		if n.Streaming.ClusterID == "" {
			return errors.New("empty cluster id")
		}
	}

	if n.JetStream.Enable {
		if n.Subject == "" {
			return errors.New("empty subject")
		}
	}

	if n.QueueDir != "" {
		if !filepath.IsAbs(n.QueueDir) {
			return errors.New("queueDir path should be absolute")

    "old key": "old value",
    "second old key": "second old value",
}
new_dict = {**old_dict, "new key": "new value"}
```

Aquí, `new_dict` contendrá todos los pares clave-valor de `old_dict` más el nuevo par clave-valor:

```Python
{
    "old key": "old value",
    "second old key": "second old value",
    "new key": "new value",
}
```

    "second old key": "second old value",
}
new_dict = {**old_dict, "new key": "new value"}
```

Hier wird `new_dict` alle Schlüssel-Wert-Paare von `old_dict` plus das neue Schlüssel-Wert-Paar enthalten:

```Python
{
    "old key": "old value",
    "second old key": "second old value",
    "new key": "new value",
}
```

import jakarta.validation.constraints.Size;

/**
 * Form class for creating new duplicate host configuration entries.
 * This form handles the creation of duplicate host mappings that redirect
 * crawling from duplicate hostnames to the regular canonical hostname.
 */
public class CreateForm {

    /**
     * Creates a new CreateForm instance.
     */
    public CreateForm() {
    }

    @Test
    void testGetProblems() {
        DefaultProblemCollector collector = new DefaultProblemCollector(null);
        assertNotNull(collector.getProblems());
        assertEquals(0, collector.getProblems().size());

        collector.add(null, "MESSAGE1", -1, -1, null);

        Exception e2 = new Exception();
        collector.add(Severity.WARNING, null, 42, 127, e2);

        return mojos;
    }

    public void setMojos(List<LifecycleMojo> mojos) {
        this.mojos = mojos;
    }

    public void set(String goals) {
        mojos = new ArrayList<>();

        if (goals != null && !goals.isEmpty()) {
            String[] mojoGoals = goals.split(",");
            mojos = Arrays.stream(mojoGoals).map(fromGoalIntoLifecycleMojo).collect(Collectors.toList());