[Java] 基于java构造方法Vector修改元素源码分析

public synchronized E set(int index, E element) {
    if (index >= elementCount)
      throw new ArrayIndexOutOfBoundsException(index);
    E oldValue = elementData(index);
    elementData[index] = element;
    return oldValue;
  }

public synchronized void setElementAt(E obj, int index) {
    if (index >= elementCount) {
      throw new ArrayIndexOutOfBoundsException(index + " >= " +
                           elementCount);
    }
    elementData[index] = obj;
  }