@Test
  public void testNullQualifier() throws Exception {
    final TableName tableName = name.getTableName();
    try (Table table = TEST_UTIL.createTable(tableName, FAMILY)) {

      // Work for Put
      Put put = new Put(ROW);
      put.addColumn(FAMILY, null, VALUE);
      table.put(put);

      // Work for Get, Scan
      getTestNull(table, ROW, FAMILY, VALUE);
      scanTestNull(table, ROW, FAMILY, VALUE);

      // Work for Delete
      Delete delete = new Delete(ROW);
      delete.addColumns(FAMILY, null);
      table.delete(delete);

      Get get = new Get(ROW);
      Result result = table.get(get);
      assertEmptyResult(result);

      // Work for Increment/Append
      Increment increment = new Increment(ROW);
      increment.addColumn(FAMILY, null, 1L);
      table.increment(increment);
      getTestNull(table, ROW, FAMILY, 1L);

      table.incrementColumnValue(ROW, FAMILY, null, 1L);
      getTestNull(table, ROW, FAMILY, 2L);

      delete = new Delete(ROW);
      delete.addColumns(FAMILY, null);
      table.delete(delete);

      Append append = new Append(ROW);
      append.addColumn(FAMILY, null, VALUE);
      table.append(append);
      getTestNull(table, ROW, FAMILY, VALUE);

      // Work for checkAndMutate using thenPut, thenMutate and thenDelete
      put = new Put(ROW);
      put.addColumn(FAMILY, null, Bytes.toBytes("checkAndPut"));
      table.put(put);
      table.checkAndMutate(ROW, FAMILY).ifEquals(VALUE).thenPut(put);

      RowMutations mutate = new RowMutations(ROW);
      mutate.add(new Put(ROW).addColumn(FAMILY, null, Bytes.toBytes("checkAndMutate")));
      table.checkAndMutate(ROW, FAMILY).ifEquals(Bytes.toBytes("checkAndPut")).thenMutate(mutate);

      delete = new Delete(ROW);
      delete.addColumns(FAMILY, null);
      table.checkAndMutate(ROW, FAMILY).ifEquals(Bytes.toBytes("checkAndMutate"))
        .thenDelete(delete);
    }
  }
Test basic puts, gets, scans, and deletes for a single row in a multiple family table.
hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestFromClientSide.java