Something

            if (level < 20 && newJobLevel > 1) return;
            if (level < 40 && newJobLevel > 2) return;
            if (level < 75 && newJobLevel > 3) return;
            // -- prevention ends

            int _price = Config.PRICE_CLASS_MASTER.get(jobLevel);
            
            if (_price > 0 && player.getInventory().getAdena() < _price)
            	{
            		player.sendPacket(new SystemMessage(SystemMessage.YOU_NOT_ENOUGH_ADENA));
            		return;
            	}
            	
            int _price = Config.PRICE_AA_CLASS_MASTER.get(jobLevel);
            
            if (_price > 0 && player.getInventory().getAncientAdena() < _price)
            	{
            		player.sendPacket(new SystemMessage(SystemMessage.YOU_NOT_ENOUGH_ANCIENTADENA));
            		return;
            	}
                        
            changeClass(player, val);