I second the idea to look for good JF from other folk, not from
stores.

It's interesting to me how every Petco/Petsmart/Petland guy that
"knows" about plants will tell you that Java Fern is a simple plant,
good for beginners. But try to find a good specimen and you will hit
a wall :-)

Java Fern is not a slow grower by any means. It doesn't grow as fast
as a stem plant but I can safely say that one can quadruple the plant
in about 2 months. Good light, CO2, somewhat high P (1 or 2), do not
move the fern and you should have success even if you start with a
beat up plant.

--Nikolay