BlockChange

BlockChangeArray bca = new BlockChangeArray(1);
BlockChange bc = bca.getBlockChange(0);
bc.setLocation(player.getLocation());
bc.setBlockID(Material.SIGN_POST.getId());
bca.setBlockChange(0,bc);
WrapperPlayServerBlockChange packet53 = new WrapperPlayServerBlockChange();
packet53.setLocation(bp);
packets.add(packet53);