I caught him by accident, jumpers were a common sight in the balcony for years in the past but certain cut-more-trees-for-light activities by fellow concerned neighbours shrink both their population and hunting grounds. Anyway I still get a jumper or two a week but this one was a nice looking and active male so I couldn't resist. I came up with a small experiment for him (less harsh than me freezing them in the fridge then defreeze them to see if they went blind), I will starve him a little bit and introduce a small black garden ant worker (Lasius niger) to see if he will even attempt an attack. Now you might ask yourself what's the point? Ants are considered a very undesirable prey by many insect predators, jumping spiders in particular with their excellent sight can react faster and better when they encounter one, so I put the ant in and the jumper avoided her at all costs. She was about 1/3 his size and was missing a leg yet the now starving to death jumper didn't even attempt a jump on her... The ant died in a few days and I was supposed to set him free since they can last a loooong time without food, but a small unexpected issue arouse that prevented me, I forgot. He starved to death in the following week or so.