code: public void trimToSize() {
  		this.modCount++;
  		final int oldCapacity = this.data.length;
  		if (this.size < oldCapacity) {
  			this.data = Arrays.copyOf(this.data, this.size);
  		}
  	}
docs: Trims the capacity of this <tt>WeakArrayList</tt> instance to be the
  list's current size.  An application can use this operation to minimize
  the storage of an <tt>WeakArrayList</tt> instance.