Server does not accept more than one client in nio

I am trying to create a chat application. I have a code that sends data from a client to a server. when one or more client logins (when the client program starts one or several times). The server does not accept other connections than the first. please help me solve this problem. here is my code:

public class Server
{

//Creating non blocking socket

public void non_Socket() throws Exception {

    ServerSocketChannel ssChannel = ServerSocketChannel.open();
    int port = 80;
    int i=0;
    ssChannel.socket().bind(new InetSocketAddress(port));
    ssChannel.configureBlocking(false);
    while(true)
    {
        SocketChannel sc = ssChannel.accept();`

        if (sc == null) 
        {
            System.out.println("Socket channel is null");
            Thread.sleep(5000);
        }
        else 
        {
            System.out.println("Socket channel is not null");
            System.out.println("Received an incoming connection from " +
                    sc.socket().getRemoteSocketAddress()); 
            new PrintRequest(sc,i).start(); 
            i++;
        }
    }
}

public static void main(String [] abc) throws Exception
{
    new Server().non_Socket();
}
}

class PrintRequest extends Thread {

public  PrintRequest(SocketChannel sc,int i) throws Exception
{
    WritableByteChannel wbc = Channels.newChannel(System.out); 
    ByteBuffer b = ByteBuffer.allocateDirect(1024); // read 1024 bytes 
    int numBytesRead = sc.read(b);

    while (numBytesRead != -1) 
    {
        b.flip();

        while (b.hasRemaining())
        { 
            wbc.write(b);
            System.out.println();
            //System.out.println("Stream  "+i);
            // System.out.println("  KKK   "+b.toString());
        }
        //b.clear();
    }    
}
}

Client Code:

public class Client extends Thread {

public void non_Client_Socket() throws Exception
{
    SocketChannel sChannel = SocketChannel.open();
    sChannel.configureBlocking(false);
    sChannel.connect(new InetSocketAddress("localhost", 80));
    while (!sChannel.finishConnect())
    {
        System.out.println("Channel is not connected yet");
    }

    System.out.println("Channel is ready to use");

    /* ----------  going to send data to server ------------*/   
    System.out.println("please enter the text");
    BufferedReader stdin=new BufferedReader(new InputStreamReader(System.in));
    while(true)
    {
        System.out.println("Enter the text");
        String HELLO_REQUEST =stdin.readLine().toString();
        if(HELLO_REQUEST.equalsIgnoreCase("end"))
        {
            break;
        }

        System.out.println("Sending a request to HelloServer");    
        ByteBuffer buffer = ByteBuffer.wrap(HELLO_REQUEST.getBytes());    
        sChannel.write(buffer); 
     }
}
     /* ----------  the data is written to sChannel server
                      will read from this channel  ------------   */

public static void main(String [] args) throws Exception
{
    new Client().non_Client_Socket();
}
}