Solved

Socket Problem.

Posted on 2006-11-09
4
264 Views
Last Modified: 2010-03-31
I have a small client server type program. On the server side I am implementing a simple
ServerSocket and I am trying to receive a buffer of bytes from the client. But I am receiving
a NullpointerException on the client side when I test this program. I cannot see what the
problem is....

PLEASE NOTE THAT IT IS MY REQUIREMENT THAT I MUST TRANSFER A byte[] FROM THE CLIENT...


Here is the Server.....
import java.io.*;
import java.net.*;

public class ComDataReceiverTest
{  
  public static void main(String[] args)
   {
     System.out.println("CounterServer started.");
 
     try {  
          ServerSocket aServerSocket = new ServerSocket(5000);
           
          for (;;)
          {
         
           Socket aSocket = aServerSocket.accept();

           InetAddress inetAdd = aSocket.getInetAddress();

           String remoteIP = inetAdd.getHostAddress();
           String remoteHostname = inetAdd.getHostName();

           int port = aSocket.getPort();

            System.out.println("Machine at IP: " + remoteIP +
                               ", with hostname: " +
                               remoteHostname + " called at port: " + port);
              //***NOTE I can see thos line is printed on the server side. So the
              //   connection is OK.
              
              
              
              //This is the area I am receiving data buffer from the Client
              DataInputStream in = new DataInputStream(aSocket.getInputStream());
        
              
              if (in== null)
               System.out.println("in Null");
              else
               System.out.println("in Not Null");
              
              //Note : I am getting "in Not Null" printed on the screen. This
              //       tells me that the DataInputStream object (in) is not null
              
              
               in.toString();
              
               byte bytes[] = null;
               int count  = in.read(bytes);
              
            aSocket.close();
           
             }
         } catch (Exception e) {System.out.println("Error: " + e);
           }  System.out.println("CounterServer stopped.");
   }}



and here is the client


import java.io.*;
import java.net.*;

public class TestClient
{  
  public static void main(String [] args)
  {  
 
   try
   {
     byte[] myBytes = {(byte)5,(byte)6,(byte)3,(byte)2,(byte)1,(byte)4};
     
     Socket t = new Socket("localhost", 5000);          
     DataOutputStream out = new DataOutputStream(t.getOutputStream());
     out.write(myBytes, myBytes.length, 0);
     t.close();
   }
   catch(Exception e)
   {
          System.out.println("Error: " + e);  
   }
  }
 
}


0
Comment
Question by:prain
  • 2
  • 2
4 Comments
 
LVL 86

Accepted Solution

by:
CEHJ earned 125 total points
ID: 17908686
>>byte bytes[] = null;

should be

byte bytes[] = new byte[256];


or some such
0
 

Author Comment

by:prain
ID: 17908737
Ok. That error is gone. But  still get the count on the ServersSide as -1.
Why is that the bytes are not tranferred?.
0
 

Author Comment

by:prain
ID: 17908769
Ok. I found why. Thanks
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 17908779
:-)
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
topping1 challenge 7 72
Free Alternative to JIRA 4 91
couple of eclipse 5 19
Way to decrease size of apk file 9 40
Go is an acronym of golang, is a programming language developed Google in 2007. Go is a new language that is mostly in the C family, with significant input from Pascal/Modula/Oberon family. Hence Go arisen as low-level language with fast compilation…
Java functions are among the best things for programmers to work with as Java sites can be very easy to read and prepare. Java especially simplifies many processes in the coding industry as it helps integrate many forms of technology and different d…
Video by: Michael
Viewers learn about how to reduce the potential repetitiveness of coding in main by developing methods to perform specific tasks for their program. Additionally, objects are introduced for the purpose of learning how to call methods in Java. Define …
This theoretical tutorial explains exceptions, reasons for exceptions, different categories of exception and exception hierarchy.

914 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

17 Experts available now in Live!

Get 1:1 Help Now