Method setBlockState

src/main/java/net/minecraft/world/World.java:357–406

Sets the block state at a given location. Flag 1 will cause a block update. Flag 2 will send the change to clients (you almost always want this). Flag 4 prevents the block from being re-rendered, if this is a client world. Flags can be added together. @param flags Flag 1 will cause a block update.

(BlockPos pos, IBlockState newState, int flags)

     * this). Flag 4 prevents the block from being re-rendered, if this is a client world. Flags can be added together.
     */
    public boolean setBlockState(BlockPos pos, IBlockState newState, int flags)
    {
        if (!this.isValid(pos))
        {
            return false;
        }
        else if (!this.isRemote && this.worldInfo.getTerrainType() == WorldType.DEBUG_WORLD)
        {
            return false;
        }
        else
        {
            Chunk chunk = this.getChunkFromBlockCoords(pos);
            Block block = newState.getBlock();
            IBlockState iblockstate = chunk.setBlockState(pos, newState);

            if (iblockstate == null)
            {
                return false;
            }
            else
            {
                Block block1 = iblockstate.getBlock();

                if (block.getLightOpacity() != block1.getLightOpacity() || block.getLightValue() != block1.getLightValue())
                {
                    this.theProfiler.startSection("checkLight");
                    this.checkLight(pos);
                    this.theProfiler.endSection();
                }

                if ((flags & 2) != 0 && (!this.isRemote || (flags & 4) == 0) && chunk.isPopulated())
                {
                    this.markBlockForUpdate(pos);
                }

                if (!this.isRemote && (flags & 1) != 0)
                {
                    this.notifyNeighborsRespectDebug(pos, iblockstate.getBlock());

                    if (block.hasComparatorInputOverride())
                    {
                        this.updateComparatorOutputLevel(pos, block);
                    }
                }

                return true;
            }
        }
    }

    public boolean setBlockToAir(BlockPos pos)
    {