EDIT

            // create JSON Object

    //        long start = System.currentTimeMillis();

            boolean isCollectionType = false;

            JSON jsonObj;

            if (entity == null){

                jsonObj = JSONObject.fromObject("{}");

            } else if(Collection.class.isAssignableFrom(entity.getClass())){

                isCollectionType = true;

                jsonObj = JSONArray.fromObject(entity, jsonConfig);

            }else if(entity instanceof String){

                jsonObj = JSONObject.fromObject("{\"String\":\""+entity.toString().replace("\"", "\\\"")+"\"}");

            } else if(entity instanceof Integer){

                jsonObj = JSONObject.fromObject("{\"Integer\":"+((Integer)entity).intValue()+"}");

            } else if(entity instanceof Boolean){

                jsonObj = JSONObject.fromObject("{\"Boolean\":"+((Boolean)entity).toString()+"}");

            } else {

                jsonObj = JSONObject.fromObject(entity, jsonConfig);

    //        System.err.println("create JSON Object " + (System.currentTimeMillis() - start));

            if(type.equals(Type.XML)){

                XMLSerializer xmlSerializer = new XMLSerializer();

                if(isCollectionType){

                    xmlSerializer.setArrayName(entity.getClass().getSimpleName());

                    Class<?> elementType = Object.class;

                    Collection<?> c = (Collection<?>)entity;

                    if(c.size() > 0){

                        elementType = c.iterator().next().getClass();

                    }

                    xmlSerializer.setObjectName(elementType.getSimpleName());

                } else if(entity != null){

                    xmlSerializer.setObjectName(entity.getClass().getSimpleName());

                String xml = xmlSerializer.write( jsonObj );

                if(type.equals(Type.XML) && xsl != null){

                    if(contextPath == null){

                        contextPath = "";

                    }

                    String basepath = dataSourceProperties.getXslBasePath(contextPath + "/xsl");

                    String replace = "\r\n<?xml-stylesheet type=\"text/xsl\" href=\"" + basepath + "/" + xsl + "\"?>\r\n";

                    xml = xml.replaceFirst("\r\n", replace);

                }

                writer.append(xml);

                // assuming json

                if(jsonpCallback != null){

                   // writer.append(jsonpCallback).append("(").append(jsonObj.toString()).append(");");

                } else {

                    writer.append(jsonObj.toString());

                }

            //TODO resp.setContentType(type);