import com.sendgrid.smtpapi.SMTPAPI; public class Example { public static void main(String[] args) { SMTPAPI header = new SMTPAPI(); // [To](http://sendgrid.com/docs/API_Reference/SMTP_API/index.html) header.addTo("[email protected]"); // or //header.addTo(["[email protected]"]); // or //header.setTos(["[email protected]", "[email protected]"]); //String[] tos = header.getTos(); // [Substitutions](http://sendgrid.com/docs/API_Reference/SMTP_API/substitution_tags.html) header.addSubstitution("key", "value"); //JSONObject subs = header.getSubstitutions(); // [Unique Arguments](http://sendgrid.com/docs/API_Reference/SMTP_API/unique_arguments.html) header.addUniqueArg("key", "value"); // or //Map map = new HashMap(); //map.put("unique", "value"); //header.setUniqueArgs(map); // or //JSONObject map = new JSONObject(); //map.put("unique", "value"); //header.setUniqueArgs(map); //JSONObject args = header.getUniqueArgs(); // [Categories](http://sendgrid.com/docs/API_Reference/SMTP_API/categories.html) header.addCategory("category"); // or //header.addCategory(["categories"]); // or //header.setCategories(["category1", "category2"]); //String[] cats = header.getCategories(); // [Sections](http://sendgrid.com/docs/API_Reference/SMTP_API/section_tags.html) header.addSection("key", "section"); // or //Map newSec = new HashMap(); //newSec.put("-section-", "value"); //header.setSections(newSec); // or //JSONObject newSec = new JSONObject(); //newSec.put("-section-", "value"); //header.setSections(newSec); //JSONObject sections = header.getSections(); // [Filters](http://sendgrid.com/docs/API_Reference/SMTP_API/apps.html) header.addFilter("filter", "setting", "value"); //header.addFilter("filter", "setting", 1); //JSONObject filters = header.getFilters(); // [ASM Group Id](https://sendgrid.com/docs/User_Guide/advanced_suppression_manager.html) header.setASMGroupId(1); //Integer groupId = header.getASMGroupId(); // [Scheduling](https://sendgrid.com/docs/API_Reference/SMTP_API/scheduling_parameters.html) header.setSendAt(1416427645); //int sendAt = header.getSendAt(); // Get Headers String headers = header.jsonString(); // If you need the unescaped JSON string. //String rawJson = header.rawJsonString(); System.out.println(headers); } }