code: public static void addColumnsToScan(Collection<String> columns, final Scan scan) {
      addColumnsToOperation(columns, new Operation() {
        @Override
        public void addColumn(byte[] family, byte[] column) {
          scan.addColumn(family, column);
        }
  
        @Override
        public void addFamily(byte[] family) {
          scan.addFamily(family);
        }
      });
    }
docs: Add a Collection of Columns to a Scanner, Only Add Single Columns
  If Their Family Isn't Already Being Added.
  @param columns
  Collection of columns to add to the scan
  @param scan
  The scanner object to add the columns to