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  • Status: Solved
  • Priority: Medium
  • Security: Public
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Unexpected end of file from server error when trying to connect to https URL

I have an application which was using MS JVM. Now this has been migrated and moved to Sun JRE 1.4.2_04.

The JRun server (ver. 4, updater 3) is behind a reverse proxy called WebSeal that receives the https requests from the client and converts into an internal request and vice versa.

When the client sends a request to the server, the process fails atleast once in five tries with the following exception.

java.net.SocketException: Unexpected end of file from server
            at sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source)
            at sun.net.www.http.HttpClient.parseHTTP(Unknown Source)
            at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
            at sun.net.www.protocol.https.PluginDelegateHttpsURLConnection.getInputStream(Unknown Source)
            at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(Unknown Source)
            at AccountListApp.AccountListApplet.send(AccountListApplet.java:480)
            at AccountListApp.AccountGrid.getLookupDetail(AccountGrid.java:9188)
            at AccountListApp.AccountGrid.DisplayFormatter(AccountGrid.java:6718)
            at AccountListApp.AccountGrid.findSpecialNew(AccountGrid.java:12269)
            at AccountListApp.AccountGrid.setCurrentAccount(AccountGrid.java:7739)
            at AccountListApp.AccountListApplet.start(AccountListApplet.java:1350)
            at sun.applet.AppletPanel.run(Unknown Source)
            at java.lang.Thread.run(Unknown Source)

We use a proxy called WebSeal (from IBM) that converts all https requests to internal requests to the JRun server. SSL-enabling is done at WebSeal and not in JRun server.

From the attached code block where the problem comes. We use a generic URL object to communicate.We do not see any relevant exceptions at the server level.

public String send(String str_request) {

             ObjectOutputStream outputToServlet = null;
             try {
                   // connect to the servlet
                   //Fill in appropriate URL depending on the webserver where its hosted
                   gridServlet = new URL(str_servletURL);
                   servletConnection = gridServlet.openConnection();
                   // inform the connection that we will send output and accept input

                   // Don't use a cached version of URL connection.
                   servletConnection.setUseCaches (false);
                   servletConnection.setDefaultUseCaches (false);

                   // Specify the content type that we will send binary data
                   servletConnection.setRequestProperty ("Content-Type", "application/octet-stream");

             }catch (Exception e){
                   System.out.println("Send :" + e);

            // System.out.println("sending Request");

             try {
                   // send the student object to the servlet using serialization
                   outputToServlet = new ObjectOutputStream(servletConnection.getOutputStream());
                  //System.out.println("created stream");
                   // serialize the object
                   //System.out.println("sendMethod: request = " + str_request);
                  //System.out.println("flushed stream");

             }catch(Exception e){
                   System.out.println("send: exception 1: " + e);

             String gridResponse = "";

             ObjectInputStream inputFromServlet = null;

             //System.out.println("b4 try ");
             String str_temp = "" ;
             try {

                   inputFromServlet = new ObjectInputStream(servletConnection.getInputStream());
                    //System.out.println("created input stream");

                    respVector = (Vector)inputFromServlet.readObject();
                           inputFromServlet.close() ;
                    //System.out.println("responseVector = " + respVector);
                    //System.out.println("responseVector befor loop::");
                    for (int i=0; i<respVector.size(); i++){

                          gridResponse  += (String)respVector.elementAt(i);
        str_temp = (String)respVector.elementAt(0) ;
          showErrorURL("0", "SESSION_EXPIRED", "SIGNON_RQV1");

             } catch(Exception e){
                    System.out.println("send: exception 2: " + e);
                    System.out.println("required exception");

             return gridResponse;


Server Details:
Windows 2000 Server
JRun 4 Updater 2
JDK 1.4.2

Client Details:
Windows 2000 Professional SP4
Internet Explorer 6.0 SP1
JRE (plug-in) 1.4.2_04

Test Case:
With the code above, it is quite straight forward to simulate the problem. The request fails atleast once in 5 times.
1 Solution
First you need to determine the size of the serialized object you wish to send to the servlet.
Then you add  
      servletConnection.setRequestProperty ("Content-Length", Integer.toString(serialized_object_size));

after the Content-Type setRequestProperty call.  This prevents unexpected end-of-data errors from the server when dealing with binary data (as found with the writeObject call).

To get the size of a serialized object, you can serialize the object to a byte stream, then get a byte array from the stream, then get the length of the array.

Check out http://www.churchillobjects.com/c/13029.html.


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