Help with "Spreadsheet"

public enum BlockType{
    GRASS, STONE
}
public record Coordinate(int x, int y, int z){}
public class Chunk{
    private BlockType[][][] blocks;//TODO initialize
    private Map<BlockType, Set<Coordinate>> blocksByType = new EnumMap<>(BlockType.class);
    public void setBlock(Coordinate coord, BlockType type){
        Set<Coordinate> oldBlockTypeCoords = blocksByType.get(type)
        if(oldBlockCoords!=null){
            oldCoordBlocks.remove(coord);
        }
        blocksByType.computeIfAbsent(type, t-> new HashSet<>()).add(coord);
        blocks[coord.x()][coord.y()][coord.z()] = type;
    }
}

public enum BlockType{
    GRASS, STONE
}
public record Coordinate(int x, int y, int z){}
public class Chunk{
    private BlockType[][][] blocks;//TODO initialize
    private Map<BlockType, Set<Coordinate>> blocksByType = new EnumMap<>(BlockType.class);
    public void setBlock(Coordinate coord, BlockType type){
        Set<Coordinate> oldBlockTypeCoords = blocksByType.get(type)
        if(oldBlockCoords!=null){
            oldCoordBlocks.remove(coord);
        }
        blocksByType.computeIfAbsent(type, t-> new HashSet<>()).add(coord);
        blocks[coord.x()][coord.y()][coord.z()] = type;
    }
}