Collection 父类  (List, ArrayList, HashSet, TreeSet, linkedList, Queue, Stack)   Map(HasMap, HasTable)

方法： （首字符为小写）

Add

Remove

Size（）

removeAll

Clear

Contains

Collection collection = new ArrayList();

collection.add(111);

collection.add("Tom Liu");

System.out.println(collection.size());

collection.remove(111);

System.out.println(collection.size());

collection.add("Liu Xin");

 

collection.forEach(obj-> System.out.println(obj));     //Lambda 表达式

 

Iterator it = collection.iterator();    //用于遍历集合元素

while(it.hasNext())

{

System.out.println((String)it.next());

}

it.forEachRemaining(oo-> System.out.println(oo));   //lambda 遍历 Iterator

 

 for (Object obj: collection)    //使用foreach 遍历

{

System.out.println(obj);

}