java - how to tell server has sent data successfully in socket programming? -

i working on problem on socket programming in java. there server , client.

1) server connected client
2) server sends n no of strings stored in array on server side(obviously ;)).
3)client doesn't know size of array
4)server receives strings server 1 one.
5)when client reads strings sends 1 msg server
6)server receives msg.
7)this process goes on(step 2-step 6) multiple times.

the problem facing is, client not know when server sends last string , waiting turn.
have solved problem using:
a)multi threading.
b)telling size of array client @ beginning of first msg

i want know there in-built function indicates if server has stoped sending data?

here code 1 iteration(step 1-step 6)

server code:

public class server { static string[] a; static dataoutputstream dos; static datainputstream dis; static serversocket server; static socket socket;  public static void main(string[] args) {      a=new string[]{"string1","string2","string3"};        try {          server=new serversocket(8080);          socket=server.accept();         dos=new dataoutputstream(socket.getoutputstream());         dis=new datainputstream(socket.getinputstream());          ///sending array values          //string temp=null;          for(int i=0;i<a.length;i++)         {             dos.writeutf(a[i]);         }          string msg_from_client=dis.readutf();         system.out.println(msg_from_client);        } catch (ioexception e) {          e.printstacktrace();     }  }   } 

client code:

public class client {   static string[] a; static dataoutputstream dos; static datainputstream dis; static socket socket; static scanner sc;  public static void main(string[] args) {     try {         socket=new socket("127.0.0.1",8080);         system.out.println("connected");         dos=new dataoutputstream(socket.getoutputstream());         dis=new datainputstream(socket.getinputstream());         sc=new scanner(system.in);          //reading server dont know size of array @ server side         string temp=null;         while((temp=dis.readutf())!=null)         {             system.out.println(temp);         }         system.out.println("out of loop");          ////now client sends msg;          string msg=sc.nextline();         dos.writeutf(msg);          system.out.println("sent");         } catch (unknownhostexception e) {         e.printstacktrace();     } catch (ioexception e) {         e.printstacktrace();     }   } } 

output @ client side:

connected
string1
string2
string3

this time learn more protocols. can setup own protocol between server , client i.e., first message server contain # of strings follow. client keep note of , request # of strings server told in first method.

edit: little more enhanced protocol

if chose path open new connection each message suggested other user, have add little more protocol. need

1. client information, server knows communication has done client previously
2. message information, server knows if client asking new message or sent message earlier client , asking next part of message.

1 can achieved allotting client id. if know how many clients dealing with, can have hardcoded value. otherwise generate @ runtime

2 message information "null" indicating client asking "any new message" him. keep in mind having "null" message_id doesn't mean skip field. have make sure add "message_id" "key" in request keep field empty. reply request expected # of strings server returning plus newly generated message_id. client use message_id in subsequent calls , tell server, asking string x of y message_id z