how can I add a new message everytime the second goes down?

[who dat]

I tried

 private int = 8;
switch (time){
            case 8:
                for(Player p : getOwner().getServer().getOnlinePlayers().values()){
                    p.sendActionBar("cc");
                }
                break;
            case 7:
                for(Player p : getOwner().getServer().getOnlinePlayers().values()){
                    p.sendActionBar("xx");
                }
                break;
            case 6:
                for(Player p : getOwner().getServer().getOnlinePlayers().values()){
                    p.sendActionBar("zz");
                }
                break;
            case 5:
                for(Player p : getOwner().getServer().getOnlinePlayers().values()){
                    p.sendActionBar("yy");
                }
                break; and so on to 0 but it doesnt update the message . help?? is there easier method?

 

[CreeperFace]

Can you explain it a bit more please?