1.     public List<E> subList(int fromIndex, int toIndex) {
    2.         subListRangeCheck(fromIndex, toIndex, size);
    3.         return new SubList(this, 0, fromIndex, toIndex);
    4.     }
    1.     private class SubList extends AbstractList<E> implements RandomAccess {
    2.         private final AbstractList<E> parent;
    3.         private final int parentOffset;
    4.         private final int offset;
    5.         int size;
    7.         SubList(AbstractList<E> parent,
    8.                 int offset, int fromIndex, int toIndex) {
    9.             this.parent = parent;
    10.             this.parentOffset = fromIndex;
    11.             this.offset = offset + fromIndex;
    12.             this.size = toIndex - fromIndex;
    13.             this.modCount = ArrayList.this.modCount;
    14.         }
    16.         public E set(int index, E e) {
    17.             rangeCheck(index);
    18.             checkForComodification();
    19.             E oldValue = ArrayList.this.elementData(offset + index);
    20.             ArrayList.this.elementData[offset + index] = e;
    21.             return oldValue;
    22.         }
    24. }
    26. SubList的set()方法，是直接修改ArrayList中elementData数组的，使用中应该注意
    28. SubList是没有实现Serializable接口的，是不能序列化的