List<E> subList(int fromIndex, int toIndex);

Returns a view of the portion of this list between the specified fromIndex, inclusive, and toIndex, exclusive. (If fromIndex and toIndex are equal, the 
returned list is empty.) The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa. 
The returned list supports all of the optional list operations supported by this list.

This method eliminates the need for explicit range operations (of the sort that commonly exist for arrays). Any operation that expects a list can be used as a 
range operation by passing a subList view instead of a whole list. For example, the following idiom removes a range of elements from a list:

      list.subList(from, to).clear();

Similar idioms may be constructed for indexOf and lastIndexOf, and all of the algorithms in the Collections class can be applied to a subList.

The semantics of the list returned by this method become undefined if the backing list (i.e., this list) is structurally modified in any way other than via 
the returned list. (Structural modifications are those that change the size of this list, or otherwise perturb it in such a fashion that iterations in 
progress may yield incorrect results.)

list.subList(from, to).clear();

package ques;  

import java.util.ArrayList;

import java.util.List;  

public class Ques0105 {  

    public static void main(String[] args) {

        List<String> list = new ArrayList<String>();

        list.add("a");  

        // 使用构造器创建一个包含list的列表list1

        List<String> list1 = new ArrayList<String>(list);

        // 使用subList生成与list相同的列表list2

        List<String> list2 = list.subList(0, list.size());

        list2.add("b");  

        System.out.println(list.equals(list1));

        System.out.println(list.equals(list2));

    }

}