Vector 源码分析

Vector类继承了类AbstractList实现了接口implements List<E>, RandomAccess, Cloneable, java.io.Serializable

存储结构是： 

protected Object[] elementData;

添加和删除方法：

  public synchronized void insertElementAt(E obj, int index) {
	modCount++;
	if (index > elementCount) {
	    throw new ArrayIndexOutOfBoundsException(index
						     + " > " + elementCount);
	}
	ensureCapacityHelper(elementCount + 1);
	System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);
	elementData[index] = obj;
	elementCount++;
    }
  public synchronized E remove(int index) {
	modCount++;
	if (index >= elementCount)
	    throw new ArrayIndexOutOfBoundsException(index);
	Object oldValue = elementData[index];

	int numMoved = elementCount - index - 1;
	if (numMoved > 0)
	    System.arraycopy(elementData, index+1, elementData, index,
			     numMoved);
	elementData[--elementCount] = null; // Let gc do its work

	return (E)oldValue;
    }

subList方法，获得一个子的链表，Collections.synchronizedList可以获得一个线程安全的List

    public synchronized List<E> subList(int fromIndex, int toIndex) {
        return Collections.synchronizedList(super.subList(fromIndex, toIndex),
                                            this);
    }

总结：vector是线程安全的