The JdbcTemplate query method can return various types of objects based on the type of result expected and the RowMapper implemented. It typically returns simpler types like integers, longs, and strings, which are essentially simple types. It can also return user-defined types when appropriate RowMappers are provided, allowing custom objects mapping from database rows. Similarly, Generic Maps (Map<String, Object>) are often returned for ad-hoc queries needing a key-value pair representation of the result set.