You might laugh, but I don't actually know if this is java moss (or some other moss) or - does hair algae look like this?
The photo shows a tiny self sustaining glass globe that holds maybe a cup+ of water. I'm holding it in my hand for the photo - you can see my pinky finger bottom right for scale. (very small hands - I'm a woman) In this tank are bladder snails (which I LOVE) - that keep this place free of trouble even in sunlight all day. It contains tiny java ferns that are struggling -- and I THOUGHT they were getting strangled by hair algae but I couldn't get time to deal with it so I left it hoping the snails would eat it. They eat everything else - but - tonight I started looking closer at this growing green mass .... and I said ... oh my gosh ... that a moss ... it's really cute. Am I right though? Oh - the roots you see on the left are from a spider plant that has its roots in the water. The tank has been going for many many months. It just works so well - and initially I was using it to throw some baby java fern in with a couple snails because I couldn't figure out where to put them. Now I actually REALLY like this tiny tank.
Sorry to ramble. Hope you can help me ID this "plant" and that it isn't actually algae.
PS: The baby java ferns had been in a clump in a closed ziploc bag full of water getting indirect sun and NO care whatsoever for 10 years. Not joking. I had no idea that any moss might have been in there back then. I'd once tried growing java moss, but it kept dying. Back then I could grow java ferns great - but killed java moss. Now the moss likes me but the ferns are struggling (well - they're getting choked out - my fault) And I am not sure it was originally true java moss - so it could be a different type.