#fixed code
                                public static String template2String(String templateContent, Map<String, Object> map,
                                         boolean isNeedFilter) {
        if (StringUtils.isEmpty(templateContent)) {
            return null;
        }
        if (map == null) {
            map = new HashMap<>();
        }
        Map<String, Object> newMap = new HashMap<>(1);

        Set<String> keySet = map.keySet();
        if (keySet.size() > 0) {
            for (String key : keySet) {
                Object o = map.get(key);
                if (o != null) {
                    if (o instanceof String) {
                        String value = o.toString();
                        value = value.trim();
                        if (isNeedFilter) {
                            value = filterXmlString(value);
                        }
                        newMap.put(key, value);
                    } else {
                        newMap.put(key, o);
                    }
                }
            }
        }
        Template t = null;
        try {
            t = new Template("", new StringReader(templateContent), new Configuration());
            StringWriter writer = new StringWriter();
            t.process(newMap, writer);
            return writer.toString();
        } catch (IOException e) {
            log.error("TemplateUtil -> template2String IOException.", e);
        } catch (TemplateException e) {
            log.error("TemplateUtil -> template2String TemplateException.", e);
        } finally {
            newMap.clear();
            newMap = null;
        }
        return null;
    }
#vulnerable code 
                                public static String template2String(String templateContent, Map<String, Object> map,
                                         boolean isNeedFilter) {
        if (StringUtils.isEmpty(templateContent)) {
            return null;
        }
        if (map == null) {
            map = new HashMap<>();
        }
        Map<String, Object> newMap = new HashMap<>(1);

        Set<String> keySet = map.keySet();
        if (keySet.size() > 0) {
            for (String key : keySet) {
                Object o = map.get(key);
                if (o != null) {
                    if (o instanceof String) {
                        String value = o.toString();
                        if (value != null) {
                            value = value.trim();
                        }
                        if (isNeedFilter) {
                            value = filterXmlString(value);
                        }
                        newMap.put(key, value);
                    } else {
                        newMap.put(key, o);
                    }
                }
            }
        }
        Template t = null;
        try {
            t = new Template("", new StringReader(templateContent), new Configuration());
            StringWriter writer = new StringWriter();
            t.process(newMap, writer);
            return writer.toString();
        } catch (IOException e) {
            log.error("TemplateUtil -> template2String IOException.", e);
        } catch (TemplateException e) {
            log.error("TemplateUtil -> template2String TemplateException.", e);
        } finally {
            if (newMap != null) {
                newMap.clear();
                newMap = null;
            }
        }
        return null;
    } 
                            #location 22 
                            #vulnerability type NULL_DEREFERENCE