List子接口的实现类:ArrayList/Vector/LinkedList
List集合:元素有序。可重复的集合,List集合默认按元素的添加顺序设置元素的索引,通过索引来访问对象
List集合源码?
public interface List<E> extends Collection<E> {
//定义了Collection集合的通用方法
int size();
boolean isEmpty();
Iterator<E> iterator();
Object[] toArray();
boolean add(E e);
boolean containsAll(Collection<?> c);
boolean addAll(Collection<? extends E> c);
boolean addAll(int index, Collection<? extends E> c);
boolean removeAll(Collection<?> c);
boolean retainAll(Collection<?> c);
@since 1.8从jdk8开始接口支持有方法体,必须为static/default修饰
default void replaceAll(UnaryOperator<E> operator) {
Objects.requireNonNull(operator);
final ListIterator<E> li = this.listIterator();
while (li.hasNext()) {
li.set(operator.apply(li.next()));
}
}
default void sort(Comparator<? super E> c) {
Object[] a = this.toArray();
Arrays.sort(a, (Comparator) c);
ListIterator<E> i = this.listIterator();
for (Object e : a) {
i.next();
i.set((E) e);
}
}
void clear();
boolean equals(Object o);
int hashCode();
//定义List集合接口专有的方法
E get(int index);
E set(int index, E element);
void add(int index, E element);
E remove(int index);
int indexOf(Object o);
int lastIndexOf(Object o);
ListIterator<E> listIterator();
ListIterator<E> listIterator(int index);
List<E> subList(int fromIndex, int toIndex);
}