gistfile1.java

     this.getServer().getScheduler().scheduleSyncRepeatingTask(this, new Runnable() {
         @Override
         public void run() {
            checkForIron();
         }
    }, 20L, 20L);

    public void checkForIron() {
        for (Player p : getServer().getOnlinePlayers()) {
            if (ArmourAbilities.hasIron(p)) { //Checks if player is wearing full set of iron
                p.addPotionEffect(new PotionEffect(PotionEffectType.SPEED, 40, 0));
            }
        }
    }