collection接口

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
public class CollectionTest
{
public static void main(String[] args)
{
Collection<String> list=new ArrayList<>();
list.add("a");
list.add("b");
list.add("c");
Iterator<String> it=list.iterator();
while (it.hasNext())
{
String string =(String)it.next();
System.out.println(string);

}
}
}