I've had Java moss coming out of my ears in the past. In a 50 gallon. No filter,no pump,just a 40 watt I sometimes put on..the rest was indirect light from the large window. No direct sunlight until it was near setting..weak. No Co2 of course. All the load I had in there was a self sustaining population of White Clouds. No other fish. Adult White Clouds and a few neon tetra like baby clouds.
Now,in my big tank this last year? I've killed Willow Moss...JAVA moss ( after my first try was a success..I crashed and burned on the 240).,,that at first did well..then HAIR ALGAE got in it and that was the end of the Java.
Right now I have a tiny bit of Christmas moss..and it does not like a flow of water over it like most plants do. It will tear apart. So,a quiet area and water with very little detritus or better none, suit it. Its hanging in there.
I want to try Java moss again. I got past the hair algae problem and I think it can do much better than the Christmas. Christmas is good though.