protected Object[] elementData;
protected int elementCount;
protected int capacityIncrement;
public Vector(int initialCapacity, int capacityIncrement) {super();if (initialCapacity < 0)throw new IllegalArgumentException("Illegal Capacity: "+initialCapacity);this.elementData = new Object[initialCapacity];//初始化数组this.capacityIncrement = capacityIncrement;//初始化默认增长值}
public Vector() {this(10);}
public Vector(int initialCapacity) {this(initialCapacity, 0);}
public synchronized void addElement(E obj) {modCount++;//结构化修改参数加1ensureCapacityHelper(elementCount + 1);//确保capacity大小满足增加元素要求elementData[elementCount++] = obj;//存储元素，数组元素索引加1}
private void ensureCapacityHelper(int minCapacity) {int oldCapacity = elementData.length;//获取数组长度if (minCapacity > oldCapacity) {//如果当前存放元素索引大于数组长度Object[] oldData = elementData;int newCapacity = (capacityIncrement > 0) ?(oldCapacity + capacityIncrement) : (oldCapacity * 2);//每次数组长度增加默认正常长度，默认增长长度为0时，扩充数组长度为原来的两倍if (newCapacity < minCapacity) {newCapacity = minCapacity;}elementData = Arrays.copyOf(elementData, newCapacity);//数组复制}}
public synchronized boolean removeElement(Object obj) {modCount++;//结构化修改计数加1int i = indexOf(obj);//获取元素位置if (i >= 0) {removeElementAt(i);//移除对应位置的元素return true;}return false;}
public int indexOf(Object o) {return indexOf(o, 0);}
public synchronized int indexOf(Object o, int index) {if (o == null) {//如果元素为null则使用==比较元素相等for (int i = index ; i < elementCount ; i++)if (elementData[i]==null)return i;} else {for (int i = index ; i < elementCount ; i++)if (o.equals(elementData[i]))//元素不为null，调用equals方法来判断是否相等return i;}return -1;}
public synchronized boolean add(E e) {modCount++;ensureCapacityHelper(elementCount + 1);elementData[elementCount++] = e;return true;}
public synchronized int capacity() {return elementData.length;}
public synchronized int size() {return elementCount;}
原文：http://blog.csdn.net/mergades/article/details/43051305