Json com subniveis

List<JSONObject> eventos = new ArrayList<JSONObject>();
	String sql = "SELECT * FROM agenda WHERE start >= '" + start + "' AND start <= '" + end + "'";
	PreparedStatement stmt = this.connection.prepareStatement(sql);
        ResultSet rs = stmt.executeQuery();

            while (rs.next()) {
            	// criando o objeto json
            	JSONObject obj = new JSONObject();
            	obj.put("id", rs.getLong("id"));
            	obj.put("title", rs.getString("title"));
            	obj.put("body", rs.getString("body"));
            	obj.put("start", rs.getString("start"));
            	obj.put("end", rs.getString("end"));
            	obj.put("user_id", rs.getLong("user_id"));
            	obj.put("pupil_id", rs.getLong("pupil_id"));
            	eventos.add(obj);
            }
                        
            JSONObject objeto = new JSONObject();
            objeto.put("events", eventos);
            
            rs.close();
            stmt.close();
            return objeto;