### Question:
SingleTableDao extends AbstractDao { @CheckForNull protected <T> T max(@Nonnull final SelectListItem<T> col, final BooleanExpression... expr) { return max(col, table(), expr); } SingleTableDao(
            final TransactionTemplate integrationExecutor,
            final SqlExecutor sqlExecutor,
            final SqlBuilder sql,
            final TableDef table,
            final ColumnDef<I> pkColumn,
            final ResultTransformer<T> reader
    );  SingleTableDao(
            final TransactionTemplate integrationExecutor,
            final SqlExecutor sqlExecutor,
            final TableDef table,
            final ColumnDef<I> pkColumn,
            final ResultTransformer<T> reader
    );   }### Answer:
@Test public void testMax() { final Integer maxHeight = _personDao.max(Person.HEIGTH); Assert.assertEquals(maxHeight, Integer.valueOf(190)); }
@Test public void testMaxWithNullResult() { final String name = _personDao.max(Person.NAME, Person.NAME.eq("nonexistent")); Assert.assertNull(name); }