public class Knockback implements Listener {

    private main plugin = main.getPlugin(main.class);

    @EventHandler
    public void onPunch(EntityDamageByEntityEvent e) {

        if (e.getEntity() instanceof Player) {
            if (e.getDamager() instanceof Player) {
                if (!(ZoutMoreKB.zout.contains(e.getDamager().getName()))){
                    Player p = (Player) e.getDamager();
                    Player t = (Player) e.getEntity();

                    Location l = t.getLocation().subtract(p.getLocation());
                    double distance = t.getLocation().distance(p.getLocation());
                    Vector v = l.toVector().multiply(0.26 / distance);
                    if (sumoArraylists.players.contains(p.getName()) && sumoArraylists.players.contains(t.getName())) {
                        t.setVelocity(v);
                    }
                }
            }
        }
    }
}