Jave fern grows best when tied to wood or rock, the plant may rot from the base up in a pot. Hoover out the dirt and bits of leaf
Forgot to say use 100% cotton thread to tie them on
If it was potted, remove the pot and the material in it.
Java fern needs to have its rhizome (the thick 'stem' at the bottom that the leaves grow off of) uncovered -- as babyfish mentioned, if the rhizome is covered, it will rot.
try puting it in a no rock area and place hevey enough rocks on it but take it out
of the pot but u don't have to take my word on it i don't have live plants only one thats growing.