code: public boolean columnFamilyExists(DBConn dbConn, String keyspace, String cfName) {
          KsDef ksDef = null;
          try {
              ksDef = dbConn.getClientSession().describe_keyspace(keyspace);
          } catch (Exception ex) {
              throw new RuntimeException("Failed to get keyspace definition for '" + keyspace + "'", ex);
          }
          
          List<CfDef> cfDefList = ksDef.getCf_defs();
          for (CfDef cfDef : cfDefList) {
              if (cfDef.getName().equals(cfName)) {
                  return true;
              }
          }
          return false;
      }
docs: Return true if the given store name currently exists in the given keyspace. This
  method can be used with a connection connected to any keyspace.
  
  @param dbConn    Database connection to use.
  @param cfName    Candidate ColumnFamily name.
  @return          True if the CF exists in the database.