if (supportsRemove) {
      int initialSize = map.size();
      boolean didRemove = entrySet.remove(entrySet.iterator().next());
      assertTrue(didRemove);
      assertEquals(initialSize - 1, map.size());
    } else {
      try {
        entrySet.remove(entrySet.iterator().next());
        fail("Expected UnsupportedOperationException.");
      } catch (UnsupportedOperationException expected) {
      }
    }

     * stack so that it is returned by the next call to {@link Iterator#next()}. If the element is
     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can

      ReferenceEntry<K, V> next = head.getNextInWriteQueue();
      return (next == head) ? null : next;
    }

    @CheckForNull
    @Override
    public ReferenceEntry<K, V> poll() {
      ReferenceEntry<K, V> next = head.getNextInWriteQueue();
      if (next == head) {
        return null;
      }

      remove(next);
      return next;
    }

    @Override

      final Runnable runnable;
      final Executor executor;
      @Nullable RunnableExecutorPair next;

      RunnableExecutorPair(Runnable runnable, Executor executor, RunnableExecutorPair next) {
        this.runnable = runnable;
        this.executor = executor;
        this.next = next;
      }
    }
  }

        protected N computeNext() {
          for (N next = visitNext(horizon); next != null; next = visitNext(horizon)) {
            Iterator<? extends N> successors = successorFunction.successors(next).iterator();
            if (!successors.hasNext()) {
              return next;
            }
            horizon.addFirst(successors);
            ancestorStack.push(next);
          }

	p.readers = tmp
	// next is the next non-preferred index.
	next := 0
	for i, ok := range prefer {
		if !ok || p.readers[i] == nil {
			continue
		}
		if i == next {
			next++
			continue
		}
		// Move reader with index i to index next.
		// Do this by swapping next and i
		p.readers[next], p.readers[i] = p.readers[i], p.readers[next]
		p.readerToBuf[next] = i
		p.readerToBuf[i] = next
		next++

    T result = uncheckedCastNullableTToT(next);
    next = null;
    return result;
  }

  @Override
  public final void remove() {
    throw new UnsupportedOperationException();
  }

    assertEquals(0, (int) iter.next());

    // verify idempotence of hasNext()
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertEquals(1, (int) iter.next());

    assertFalse(iter.hasNext());

    // Make sure computeNext() doesn't get invoked again
    assertFalse(iter.hasNext());

    try {
      iter.next();
      fail("no exception thrown");

    assertEquals(0, (int) iter.next());

    // verify idempotence of hasNext()
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertTrue(iter.hasNext());
    assertEquals(1, (int) iter.next());

    assertFalse(iter.hasNext());

    // Make sure computeNext() doesn't get invoked again
    assertFalse(iter.hasNext());

    try {
      iter.next();
      fail("no exception thrown");

        throw new IllegalStateException();
      }
      iterator.remove();
    }
  }

  public void testCanCatchSunJavaBug6529795InTargetIterator() {
    try {
      /* Choose 4 steps to get sequence [next, next, next, remove] */
      new IteratorTester<Integer>(
          4, MODIFIABLE, newArrayList(1, 2), IteratorTester.KnownOrder.KNOWN_ORDER) {
        @Override
        protected Iterator<Integer> newTargetIterator() {