code: private final void growToHold(final int length) {
  		if (length > stack.length) {
  			final int[] newStack = new int[Math.max(length, stack.length * 2)];
  			System.arraycopy(stack, 0, newStack, 0, stack.length);
  			stack = newStack;
  		}
  	}
docs: Resize Stack