fix ResultSet not positioned properly, perhaps you need to call next.

src/main/java/ru/di9/jdbc/JdbcTemplateImpl.java

@@ -56,7 +56,7 @@ public class JdbcTemplateImpl implements JdbcTemplate {
              PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
             psp.process(preparedStatement);
             try (ResultSet resultSet = preparedStatement.executeQuery()) {
-                return rse.extractData(resultSet);
+                return resultSet.next() ? rse.extractData(resultSet) : null;
             }
         } catch (SQLException e) {
             throw throwDataAccessException(sql, e);