j and k are from vi where those were the arrow keys. h(left)j(down)k(up)l(right) are used in a lot of apps for the reason that a lot of programmers use vi keybi

j and k are from vi where those were the arrow keys. h(left)j(down)k(up)l(right) are used in a lot of apps for the reason that a lot of programmers use vi keybindings.