return new Iterator<U>() {
            @Override
            public boolean hasNext() {
                return it.hasNext();
            }

            @Override
            public U next() {
                return mapper.apply(it.next());
            }
        };
    }

    @Override
    public int size() {
        return list.size();
    }

    assertTrue(broken.hasNext());
    // We can't retrieve even the known first element:
    try {
      broken.next();
      fail();
    } catch (MyException expected) {
    }
    try {
      broken.next();
      fail();
    } catch (MyException expected) {
    }
  }

  private static Iterator<Integer> newDoubler(int first, final int last) {

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

The next sections assume you already read the main [Tutorial - User Guide: Security](../../tutorial/security/index.md){.internal-link target=_blank}.

    }.test();
  }

  public void testIteratorNoSuchElementException() {
    Iterator<E> iterator = collection.iterator();
    while (iterator.hasNext()) {
      iterator.next();
    }

    try {
      iterator.next();
      fail("iterator.next() should throw NoSuchElementException");
    } catch (NoSuchElementException expected) {
    }
  }

      // unlink guard from activeGuards
      for (Guard p = activeGuards, pred = null; ; pred = p, p = p.next) {
        if (p == guard) {
          if (pred == null) {
            activeGuards = p.next;
          } else {
            pred.next = p.next;
          }
          p.next = null; // help GC
          break;
        }
      }
    }
  }

  /*

		onConflictDonothing = mode&ScanOnConflictDoNothing != 0
	)

	db.RowsAffected = 0

	switch dest := db.Statement.Dest.(type) {
	case map[string]interface{}, *map[string]interface{}:
		if initialized || rows.Next() {
			columnTypes, _ := rows.ColumnTypes()
			prepareValues(values, db, columnTypes, columns)

			db.RowsAffected++
			db.AddError(rows.Scan(values...))

			mapValue, ok := dest.(map[string]interface{})

        try {
          Event nextEvent;
          while ((nextEvent = queueForThread.poll()) != null) {
            while (nextEvent.subscribers.hasNext()) {
              nextEvent.subscribers.next().dispatchEvent(nextEvent.event);
            }
          }
        } finally {
          dispatching.remove();
          queue.remove();
        }
      }
    }

    Iterator<String> keyIterator = keys.iterator();
    keyIterator.next();
    keyIterator.remove();
    assertFalse(underlying.containsKey("c"));

    Collection<String> values = map.values();
    values.remove("4");
    assertFalse(underlying.containsKey("d"));

    Iterator<String> valueIterator = values.iterator();
    valueIterator.next();
    valueIterator.remove();
    assertFalse(underlying.containsKey("e"));

  @CheckForNull
  protected Entry<E> standardFirstEntry() {
    Iterator<Entry<E>> entryIterator = entrySet().iterator();
    if (!entryIterator.hasNext()) {
      return null;
    }
    Entry<E> entry = entryIterator.next();
    return Multisets.immutableEntry(entry.getElement(), entry.getCount());
  }

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {
    return delegate().lastEntry();
  }

  /**

  @CollectionSize.Require(SEVERAL)
  public void testRemovePresentConcurrentWithEntrySetIteration() {
    try {
      Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
      getMap().remove(k0());
      iterator.next();
      fail("Expected ConcurrentModificationException");
    } catch (ConcurrentModificationException expected) {
      // success
    }
  }