It is as if the roots become sticky, or find some way to adhere themselves to the seemingly smooth surface. The roots can become quite long when they are not attached. The heart of a Java Fern is its durable rhizome, which creeps in length and thickness with age, and eventually branches out to cover wider areas. This could take a year to accomplish, though, as rhizome growth is slower than leaf development. The leaves of Java Fern are equally hardy.
Healthy leaves are a stunning dark green with a leathery texture.
A well-kept specimen can have a few leaves up to 10 inches long and 1.5 inches wide. This form is more like a bush. I think this may a species difference. Regardless of type, to encourage taller growth, new plants should be pruned so more energy is available for rhizome and leaf growth. Trust me - the leaves will come back, albeit taller.