public Get addColumn(byte[] family, byte[] qualifier) {
    NavigableSet<byte[]> set = familyMap.get(family);
    if (set == null) {
      set = new TreeSet<>(Bytes.BYTES_COMPARATOR);
      familyMap.put(family, set);
    }
    if (qualifier == null) {
      qualifier = HConstants.EMPTY_BYTE_ARRAY;
    }
    set.add(qualifier);
    return this;
  }
Get the column from the specific family with the specified qualifier.
<p>
Overrides previous calls to addFamily for this family.
@param family    family name
@param qualifier column qualifier
@return the Get objec
hbase-client/src/main/java/org/apache/hadoop/hbase/client/Get.java