java - Why am I getting a false value at if (users.contains(user))? -

i think user.contains not reading every line , checking first line. had working right earlier(i testing duplicate user portion of code), program skipping :

{                 joptionpane.showmessagedialog(null, "duplicate user found.");              goahead=false;             dispose();             } 

i not sure did, or how managed break own program. skipping way to:

else { if (hs.contains(new string(un+" "+pw))) {                  joptionpane.showmessagedialog(null,"user, found access granted!");                     dispose();                 } 

where did go wrong?

private void submitactionperformed(java.awt.event.actionevent evt) {                                            string un = username.gettext().trim();         string pw = password.gettext().trim();         hashset hs= new hashset();         hashset users = new hashset();          boolean goahead=true;          try {             scanner scan = new scanner(new file("login.txt"));             while (scan.hasnextline()) {                  string authenticator = scan.nextline().trim();                 string[] autparts=authenticator.split(" ");                  string user = autparts[0].trim();                 if (goahead){                     if (users.contains(user)) {                         if (user.equals(un)) {                                 joptionpane.showmessagedialog(null, "duplicate user found.");                              goahead=false;                             dispose();                         }                     } else {                         hs.add(authenticator);                         users.add(user);                     }                 }             }         } catch (exception ex) {              ex.printstacktrace();          }          if (goahead) {             if (createaccount.isselected() & (hs.contains(new string(un+" "+pw)))){                 joptionpane.showmessagedialog(null,"user exsist! no need create new account. ");                 dispose();             } else {                  if (hs.contains(new string(un+" "+pw))) {                      joptionpane.showmessagedialog(null,"user, found access granted!");                     dispose();                 }  else {                      if (createaccount.isselected()){                         try {                             printwriter output = new printwriter(new bufferedwriter(new filewriter("login.txt", true)));                              output.println(un+" "+pw);                             output.close();                          } catch (ioexception ex) {                             system.out.printf("error %s/n", ex );                         }                            joptionpane.showmessagedialog(null,"welcome!"+" " + un+" "+"please relogin now");                         dispose();                     }else {                         joptionpane.showmessagedialog(null, "user doesn't exist or password incorrect. ");                          dispose();                     }                 }             }         } 

the following output , whats in txt file. :

i have formatted code now:

string un = username.gettext().trim(); if (goahead){        if (users.contains(user))         {          if (user.equals(un))           {                  joptionpane.showmessagedialog(null, "duplicate user found.");               goahead=false;              dispose();          }        }         else         {         hs.add(authenticator);         users.add(user);        } } 

now when flag goahead set false dont need reset true somewhere? if hashset contains user why need again compare name of user? should have defined equals user itself. nope?