public int getColumn(BucketId bucketId) {
        int ret = (int)(bucketId.getId() & (getNumBuckets(numBucketBits) - 1));
        if (ret >= bucketToColumn.length) {
            log.log(Level.SEVERE,
                    "The bucket distribution map is not in sync with the number of bucket bits. " +
                    "This should never happen! Distribution is broken!!");
            return 0;
        }
        return bucketToColumn[ret];
    }
This method maps the given bucket id to its corresponding column.

@param bucketId The bucket whose column to lookup.
@return The column to distribute the bucket to.
vdslib/src/main/java/com/yahoo/vdslib/BucketDistribution.java