BufferedReader readLine() not returning null

Question

I'm trying write an SMTP client using Socket.
I'm sending EHLO command to the SMTP server is is returning multiline response. When I tried to read this multiline response using the BufferedReader in a while loop, it is never returning null.
Following is my code snippet
while(true)
                data=reader.readLine();
                multilineData +=data+"\r\n";
                if(data==null )
                    break;
                }why it is not returning?

Answer 1

I have written debug statements.
It is printing the following lines and it still expecting something from the server even though server has finished sending all the response.
250-mail.merakdemo.com Hello <hostname>, pleased to meet you.
250-ENHANCEDSTATUSCODES
250-SIZE
250-EXPN
250-ETRN
250-ATRN
250-DSN
250-CHECKPOINT
250-8BITMIME
250-AUTH CRAM-MD5 DIGEST-MD5 LOGIN PLAIN
250-AUTH=LOGIN
250-STARTTLS
250 HELP
This is the end of response from server.
And even I tried to break the while loop by checking the "HELP" String in the response. It is breaking the loop, but it is never returning the control.
Following is the Code snippet:
private String pullMultilineData(BufferedReader reader) throws CommunicationException
       String multilineData="";
       String data="";
        try
            while(true)
                data=reader.readLine();
                multilineData +=data+"\r\n";
                // as per SMTP Protocol last line is without "-"
                if(data==null || data.equals("") || data.indexOf("-")==-1)
                                    break;
               logger.log(Level.DEBUG, "Data: "+data);
        catch(IOException ioe)
            logger.log(Level.ERROR, "I/O exception: "+ioe);
            throw new CommunicationException("unable to pull the respose, i/o error occured");
       return multilineData;
    }