/** * @Describe * @Author Double LiFly * @date 2021/4/22 18:46 */ public class ListDemo02 { public static void main(String[] args) { /** * 常用方法 * void add(int index,E element) 在此集合中的指定位置插入指定的元素 * E remove(int index) 删除指定索引处的元素,返回被删除...
import java.util.List;publicclassTestArrayList {publicstaticvoidmain(String[] args) {//Collection list = new ArrayList();List list =newArrayList();//添加元素list.add("aa"); list.add("bb"); list.add("cc"); list.add(2,"dd");//遍历输出for(inti=0;i<list.size();i++){ Stringstring...
EnumSet complementOf(EnumSet e): 创建一个其元素类型与指定EnumSet里元素类型相同的EnumSet集合,新EnumSet集合包含原EnumSet集合所不包含的、此类枚举类剩下的枚举值(即新EnumSet集合和原EnumSet集合的集合元素加起来是该枚举类的所有枚举值)。 EnumSet copyOf(Collection c): 使用一个普通集合来创建EnumSet集合。 EnumS...
public boolean add(E e) {//e="java" return map.put(e, PRESENT)==null; //PRESENT 就是 private static final Object PRESENT = new Object(); } 3.执行put()方法,该方法会执行hash(key),得到key对应的hash值,算法(h = key.hashCode()) ^ (h >>> 16) public V put(K key, V value) {...
Beware that, unlike in most collections, the size method is NOT a constant-time operation. Because of the asynchronous nature of these queues, determining the current number of elements requires a traversal of the elements, and so may report inaccurate results if this collection is modified during...
Performance is likely to be just slightly below that of HashMap, due to the added expense of maintaining the linked list, with one exception: Iteration over the collection-views of a LinkedHashMap requires time proportional to the size of the map, regardless of its capacity. Iteration over a...
Serializable,Cloneable,Iterable<E>,Collection<E>,Set<E> public classLinkedHashSet<E>extendsHashSet<E> implementsSet<E>,Cloneable,Serializable Hash table and linked list implementation of theSetinterface, with predictable iteration order. This implementation differs fromHashSetin that it maintains a dou...
(add,containsandremove), assuming the hash function disperses elements properly among the buckets. Performance is likely to be just slightly below that ofHashMap, due to the added expense of maintaining the linked list, with one exception: Iteration over the collection-views of aLinkedHashMap...
public LinkedBlockingQueue(Collection<? extends E> c) { this(Integer.MAX_VALUE); final ReentrantLock putLock = this.putLock; putLock.lock(); // Never contended, but necessary for visibility try { int n = 0; for (E e : c) {
接口Collection<E> 中的 removeAll。 返回值: 如果集合发生更改,removeAll() 方法将返回一个布尔值 'true',否则返回 false。 抛出: 如果指定的集合不支持空元素或包含一个或多个空元素,则抛出 NullPointerException。 例子1 importjava.util.ArrayList;importjava.util.List;importjava.util.concurrent.ConcurrentLinke...