gistfile1.txt

 public WorldGenTallGrass(BlockTallGrass.EnumType p_i45629_1_)
    {
        this.field_175907_a = Blocks.tallgrass.getDefaultState().withProperty(BlockTallGrass.TYPE, p_i45629_1_);
    }
    
    or 
    
    public boolean generate(World worldIn, Random p_180709_2_, BlockPos p_180709_3_)
    {
        Block block;

        do
        {
            block = worldIn.getBlockState(p_180709_3_).getBlock();
            if (!block.isAir(worldIn, p_180709_3_) && !block.isLeaves(worldIn, p_180709_3_)) break;
            p_180709_3_ = p_180709_3_.down();
        } while (p_180709_3_.getY() > 0);

        for (int i = 0; i < 128; ++i)
        {
            BlockPos blockpos1 = p_180709_3_.add(p_180709_2_.nextInt(8) - p_180709_2_.nextInt(8), p_180709_2_.nextInt(4) - p_180709_2_.nextInt(4), p_180709_2_.nextInt(8) - p_180709_2_.nextInt(8));

            if (worldIn.isAirBlock(blockpos1) && Blocks.tallgrass.canBlockStay(worldIn, blockpos1, this.field_175907_a))
            {
                worldIn.setBlockState(blockpos1, this.field_175907_a, 2);
            }
        }

        return true;