java - Having problems login into Gmail imaps (not using javamail) tag error -

i trying create typestate client program in java speaks gimaps having trouble getting login in. when enter details sends * bad invalid tag. presume tag sending. here's code i'll explain more.

     public class cmain  {         static final string crlf = "\r\n";         public static string saferead(bufferedreader readerc) {         string readline = "";         try {             readline = readerc.readline();         }         catch(ioexception e) {             system.out.println("input/output error, unable read");             system.exit(+1);         }         return readline;     }     public static void main(string[] args) {         crole currentc = new crole();         bufferedreader readerc = new bufferedreader(new inputstreamreader(system.in));         system.out.println("connecting: ");          string payload2 = currentc.receive_acceptedstringfroms();         system.out.println("received s: " + payload2);         //connected - decide if want login         system.out.print("choose label among [login, quit]: ");         string label1 = saferead(readerc).equals("login") ? "1" : "2";           switch(currentc.send_choice1labeltos(label1).getenum()){             case choice1.login:             system.out.print("send s: ");             //when here enter username@gmail.com password             string payload3 = saferead(readerc);             currentc.send_loginstringtos(payload3);             string response = currentc.receive_choice2labelfroms();             system.out.println("server: " + response);              string payload4 = currentc.receive_okstringfroms();             system.out.println("received s: " + payload4);             system.out.print("choose label among [inbox, quit]: ");             string label2 = saferead(readerc).equals("inbox") ? "1" : "2";             switch(currentc.send_choice3labeltos(label2).getenum()){                 case choice3.inbox:                 system.out.print("send s: ");                 string payload5 = saferead(readerc);                 currentc.send_inboxstringtos(payload5);                  break;                 case choice3.quit:                 system.out.print("send s: ");                 string payload6 = saferead(readerc);                 currentc.send_quitstringtos(payload6);                 break;                 }           break;         case choice1.quit:         system.out.print("send s: ");         string payload8 = saferead(readerc);         currentc.send_quitstringtos(payload8);         break;         }     } }      public class crole  {        private bufferedreader socketsin = null;        private printwriter socketsout = null;        private socket client;        public crole(){            sslsocketfactory sslsocketfactory = (sslsocketfactory)sslsocketfactory.getdefault();         try {             client = (sslsocket) sslsocketfactory.createsocket("imap.gmail.com", 993);             system.out.println("connect host");         }         catch(ioexception e) {             system.out.println("unable listen on ports");             system.exit(+1);         }         try {             socketsin = new bufferedreader(new inputstreamreader(client.getinputstream()));             socketsout = new printwriter(client.getoutputstream(), true);         }         catch(ioexception e) {             system.out.println("read failed");             system.exit(+1);         }     }     public void send_connectstringtos(string payload) {         this.socketsout.println(payload);     }     public string receive_acceptedstringfroms() {         string line = "";         try {             line = this.socketsin.readline();         }         catch(ioexception e) {             system.out.println("input/outpur error.");             system.exit(+1);         }         return line;     }     public choice1 send_choice1labeltos(string payload) {         this.socketsout.println(payload);         int intlabelchoice1 = integer.parseint(payload);         //int intlabelchoice1 = 1;         switch(intlabelchoice1){             case 1:             return new choice1(choice1.login);             case 2:             default:             return new choice1(choice1.quit);         }     }     public void send_loginstringtos(string payload) {         this.socketsout.println(payload);     }     public string receive_choice2labelfroms() {         string line = "";         try {             line = this.socketsin.readline();         }         catch(ioexception e) {             system.out.println("input/outpur error.");             system.exit(+1);         }         return line;     }     public string receive_okstringfroms() {         string line = "";         try {             line = this.socketsin.readline();         }         catch(ioexception e) {             system.out.println("input/outpur error.");             system.exit(+1);         }         return line;     }     public choice3 send_choice3labeltos(string payload) {         this.socketsout.println(payload);         int intlabelchoice3 = integer.parseint(payload);         switch(intlabelchoice3){             case 1:             return new choice3(choice3.inbox);             case 2:             default:             return new choice3(choice3.quit);         }     }     public void send_inboxstringtos(string payload) {         this.socketsout.println(payload);     }     public void send_quitstringtos(string payload) {         this.socketsout.println(payload);     }     public string receive_quitstringfroms() {         string line = "";         try {             line = this.socketsin.readline();         }         catch(ioexception e) {             system.out.println("input/outpur error.");             system.exit(+1);         }         return line;     } } 

so case of string sending gmail? have sent following strings: username@gmail.com password; a001 login username@gmail.com password; a001 username@gmail.com password; username@gmail.com, password. , have had no luck these.

or oauth?

i not using javamail , not wish use it.

thank

problem semi fixed. rewrote simple program not using typestating method of programming , work not sending incorrect tag there in typestated code causing problems.