public class BlockRegen implements Listener {

	public static ArrayList<Block> block = new ArrayList<Block>();

	@EventHandler
	public void onBlockBreak(BlockBreakEvent e)
	{
		Player p = (Player) e.getPlayer();
		Block b = e.getBlock();
				timer(b, Material.GOLD_ORE);
				e.setCancelled(true);
				b.setType(Material.COBBLESTONE);
				block.add(b);
				for(ItemStack is : b.getDrops())
				{
				p.getInventory().addItem(is);
				}
				b.getDrops().clear();
			}

	  public void timer(final Block b, final Material m)
	  {
	    Bukkit.getScheduler().runTaskLater(TowerInvasion.plugin, new Runnable()
	    {
	      public void run()
	      {
	       b.setType(m);
	       block.remove(b);
	      }
	    }
	    , 600L);
	}

		@EventHandler
		public void onBlockBreak2(BlockBreakEvent e)
		{
			Block b = e.getBlock();
				if(block.contains(b))
					e.setCancelled(true);
				}
			}