java - how to create custom reports in testng -

i have following java code:

public class login {     string login_status = null;     string login_message = null;      @test     @parameters({"username","password"})     public void execute(string username, string password) throws ioexception {         try {             config.driver.findelement(by.linktext("log in")).click();             config.driver.findelement(by.id("user_login")).sendkeys(username);             config.driver.findelement(by.id("user_pass")).sendkeys(password);             config.driver.findelement(by.id("wp-submit")).click();             // perform validation here             boolean expvalue = config.driver.findelement(by.xpath("//a[@rel='home']")).isdisplayed();             if (expvalue) {                 login_status = "pass";                 login_message="login successfull user:" + username + ",password:" + password + ",\n expected: rtmedia demo site link should present on home page of rtmedia actual: rtmedia link present on home page of rtmedia. details:na";             }         } catch(exception generalexception) {             login_status = "fail";             login_message = "login unsuccessfull user:" + username + ",password:" + password + ",\n expected: rtmedia demo site link should present on home page of rtmedia actual: rtmedia link  not present on home page of rtmedia. details:exception occurred:"+generalexception.getlocalizedmessage();             // file scrfile = ((takesscreenshot) config.driver).getscreenshotas(outputtype.file);              // fileutils.copyfile(scrfile, new file("c:\\users\\public\\pictures\\failure.png"));           } {             assert.asserttrue(login_status.equalsignorecase("pass"), login_message);         }        } } 

i wrote above java code login functionality , want create reports whatever result (pass or fail) , should stored in folder? have no idea generating reports , found reports automatically generated testng when run test gets overwritten, not me. help?

there quite few ways can achieve this

1. if you're using xml report can implement ireporter , create listener. have override method called generatereport(list<xmlsuite> xmlsuites, list<isuite> suites, string outputdirectory) , can have own logic save output in different folder everytime run test case.
2. there attribute in testng called filefragmentationlevel if set 3 think report not overwritten. it's in xml reporter class
3. you can create listener extend testlisteneradapter , override onstart(itestcontext testcontext) method testoutput folder everytime. don't prefer method.

i prefer #1.