code: public void ensureCapacity(int minCapacity) {
  		modCount++;
  		int oldCapacity = elementData.length;
  		if (minCapacity > oldCapacity) {
  			int oldData[] = elementData;
  			int newCapacity = (oldCapacity * 3)/2 + 1;
  				if (newCapacity < minCapacity)
  				newCapacity = minCapacity;
  			elementData = new int[newCapacity];
  			System.arraycopy(oldData, 0, elementData, 0, size);
  		}
  	}
docs: Increases the capacity of this <tt>ArrayList</tt> instance, if
  necessary, to ensure  that it can hold at least the number of elements
  specified by the minimum capacity argument.
  
  @param   minCapacity   the desired minimum capacity.