### Question:
PriorityList extends AbstractList<T> { @Deprecated @Override public void add(int index, T element) { throw new UnsupportedOperationException("不支持添加到指定位置"); } PriorityList(int defaultPriority);  PriorityList(); boolean addItem(T item, int priority); @Deprecated @Override void add(int index, T element); boolean addItem(T item); boolean add(T item); boolean remove(Object item); int size(); T get(int index); int getPriory(int index); @Override T set(int index, T element); @NonNull @Override Iterator<T> iterator();  }### Answer:
@Test public void testItr() { List<Object> list = new ArrayList<>(); list.add("5"); ListIterator<Object> iterator = list.listIterator(); Object next = iterator.next(); System.out.println(next); Object previous = iterator.previous(); System.out.println(previous); }