Stream corrupted exception

[Nithyanand]

I am sending a serialized object from servlet to applet, I am getting it to the input stream, when I try to pass to the ObjectInputStream constructor, I am getting an Stream corrupted Exception.,and it says object not serialized properly, well I have serialized it on the servlet.
The error occurs in the line below

<javacode>
ObjectInputStream oi = new ObjectInputStream(in)
//where in the inputsream object from the server
</javacode>

[DHunter21]

Two Questions:
1. Does the class file for this object reside on the applet side as well?
2. And if so, are you sure its an updated version?

[Nithyanand]

I have the updated class file on the client machine ie where my applet is running.. Any other suggestions..

[DHunter21]

Do you use the Stream before you assign the ObjectInputStream to it? Do you use it as a Data Stream first (for example) , and then try to reassign the stream?

I've got Object Streams working throught sockets on my system, but without some code, I'm shooting in the dark trying to help.

[Nithyanand]

Sorry for keeping you in dark..

This is my applet code:
<java code>
import java.awt.*;
import java.applet.*;
import java.net.*;
import HttpMessage.*;
import java.io.*;
import java.util.*;
import DayTimeSer.*;

public class Applet1 extends Applet
{
public void init()
{

setLayout(null);
setSize(626,404);
label1.setText("Daytime Applet");
add(label1);
label1.setBackground(java.awt.Color.lightGray);
label1.setForeground(java.awt.Color.blue);
label1.setFont(new Font("Dialog", Font.PLAIN, 40));
label1.setBounds(180,36,288,60);
add(textField1);
textField1.setBounds(204,144,235,29);
add(textField2);
textField2.setBounds(204,192,233,30);
add(textField3);
textField3.setBounds(204,240,233,33);
add(textField4);
textField4.setBounds(204,288,230,31);
button1.setLabel("Refresh");
add(button1);
button1.setBackground(java.awt.Color.lightGray);
button1.setBounds(276,348,109,33);
//}}

//{{REGISTER_LISTENERS
SymAction lSymAction = new SymAction();
button1.addActionListener(lSymAction);
//}}
}

//{{DECLARE_CONTROLS
java.awt.Label label1 = new java.awt.Label();

java.awt.TextField textField2 = new java.awt.TextField();

ObjectInputStream result=null;


public void start(){
refresh();
}

public void refresh(){

textField2.setText(getDateUsingHttpObject());

}


private String getDateUsingHttpObject(){

try{
URL url = new URL("http://PServer21:8080/servlet/DayTimeSer");

HttpMessage msg = new HttpMessage(url);
Properties props = new Properties();
props.put("format","object");
System.out.println("hai"+(msg.sendGetMessage(props)).toString());

InputStream in = msg.sendGetMessage(props);

System.out.println("hai1****");
//erro occurs in the following line
try{
ObjectInputStream result= new ObjectInputStream(in);
}catch(StreamCorruptedException e){
e.printStackTrace();
}
System.out.println("hai1****");
Object obj = result.readObject();

Date date = (Date)obj;
return date.toString();
}
catch(Exception e ){
e.printStackTrace();
return null;
}
}


class SymAction implements java.awt.event.ActionListener
{
public void actionPerformed(java.awt.event.ActionEvent event)
{
Object object = event.getSource();
if (object == button1)
button1_ActionPerformed(event);
}
}

void button1_ActionPerformed(java.awt.event.ActionEvent event)
{
refresh();

}
}
</javacode>

this is my servletcode

<javacode>
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DayTimeSer extends HttpServlet

{
public Date getDate(){
return new Date();
}
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
{
if("Object".equals(req.getParameter("format"))){
ObjectOutputStream out = new ObjectOutputStream(resp.getOutputStream());
out.writeObject(getDate());

}
else{
PrintWriter out = resp.getWriter();
out.println(getDate().toString());
}


}

public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
{
doGet(req,resp);

}

}

</javacode>

This is httpmessage.java used for the interaction

<javacode>
public class HttpMessage {

URL servlet = null;
String args = null;

/**
* Constructs a new HttpMessage that can be used to communicate with the
* servlet at the specified URL.
*
* @param servlet the server resource (typically a servlet) with which
* to communicate
*/
public HttpMessage(URL servlet) {
this.servlet = servlet;
}

/**
* Performs a GET request to the servlet, with no query string.
*
* @return an InputStream to read the response
* @exception IOException if an I/O error occurs
*/
public InputStream sendGetMessage() throws IOException {
return sendGetMessage(null);
}

/**
* Performs a GET request to the servlet, building
* a query string from the supplied properties list.
*
* @param args the properties list from which to build a query string
* @return an InputStream to read the response
* @exception IOException if an I/O error occurs
*/
public InputStream sendGetMessage(Properties args) throws IOException {
String argString = ""; // default

if (args != null) {
argString = "?" + toEncodedString(args);
}
URL url = new URL(servlet.toExternalForm() + argString);

// Turn off caching
URLConnection con = url.openConnection();
con.setUseCaches(false);

return con.getInputStream();
}

/**
* Performs a POST request to the servlet, with no query string.
*
* @return an InputStream to read the response
* @exception IOException if an I/O error occurs
*/
public InputStream sendPostMessage() throws IOException {
return sendPostMessage(null);
}

/**
* Performs a POST request to the servlet, building
* post data from the supplied properties list.
*
* @param args the properties list from which to build the post data
* @return an InputStream to read the response
* @exception IOException if an I/O error occurs
*/
public InputStream sendPostMessage(Properties args) throws IOException {
String argString = ""; // default
if (args != null) {
argString = toEncodedString(args); // notice no "?"
}

URLConnection con = servlet.openConnection();

// Prepare for both input and output
con.setDoInput(true);
con.setDoOutput(true);

// Turn off caching
con.setUseCaches(false);

// Work around a Netscape bug
con.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded");

// Write the arguments as post data
DataOutputStream out = new DataOutputStream(con.getOutputStream());
out.writeBytes(argString);
out.flush();
out.close();

return con.getInputStream();
}

/**
* Performs a POST request to the servlet, uploading a serialized object.
* <p>
* The servlet can receive the object in its <tt>doPost()</tt> method
* like this:
* <pre>
* ObjectInputStream objin =
* new ObjectInputStream(req.getInputStream());
* Object obj = objin.readObject();
* </pre>
* The type of the uploaded object can be retrieved as the subtype of the
* content type (<tt>java-internal/<i>classname</i></tt>).
*
* @param obj the serializable object to upload
* @return an InputStream to read the response
* @exception IOException if an I/O error occurs
*/
public InputStream sendPostMessage(Serializable obj) throws IOException {
URLConnection con = servlet.openConnection();

// Prepare for both input and output
con.setDoInput(true);
con.setDoOutput(true);

// Turn off caching
con.setUseCaches(false);

// Set the content type to be java-internal/classname
con.setRequestProperty("Content-Type",
"java-internal/" + obj.getClass().getName());

// Write the serialized object as post data
ObjectOutputStream out = new ObjectOutputStream(con.getOutputStream());
out.writeObject(obj);
out.flush();
out.close();

return con.getInputStream();
}

/*
* Converts a properties list to a URL-encoded query string
*/
private String toEncodedString(Properties args) {
StringBuffer buf = new StringBuffer();
Enumeration names = args.propertyNames();
while (names.hasMoreElements()) {
String name = (String) names.nextElement();
String value = args.getProperty(name);
buf.append(URLEncoder.encode(name) + "=" + URLEncoder.encode(value));
if (names.hasMoreElements()) buf.append("&");
}
return buf.toString();
}
}
</javacode>


hope you can now find an answer to the problem

thank u in advance
Nithyanand