Java Servlet Programming
by Jason Hunter with William Crawford


Unconfirmed error reports are from readers. They have not yet
been approved or disproved by the author or editor and represent
solely the opinion of the reader.


This page was updated April 27, 2001.


Here's the key to the markup:

        [page-number]: serious technical mistake
        {page-number}: minor technical mistake
        <page-number>: important language/formatting problem
        (page-number): language change or minor formatting problem
        ?page-number?: reader question or request for clarification


UNCONFIRMED errors and suggestions from readers:


[1]  Multipart classes;
I'm getting an IOException: Corrupt form data: no leading boundary, when I 
use the MultipartParser, and paste any word document piece into a textarea 
in my form. I can't determine what characters are causing this. Do you have 
any ideas? I would like to try to filter out the characters on the client 
side to get around the bug. The form works great when I type in text by hand.


[29]  Example 2-4;
The Server Side Include that prints the Current time in three different 
places doesnot work..All the three servlet tags in the .shtml file that 
make a call to the Currenttime servlet displays only the system current 
time...the problem is with the <param name=zone >
This parameter name "zone" doesnot take the value specified in the value 
attribute of the tag..it simply shows null..

If the order of the servlet tags is changed...i.e if i put the tag
<servlet code=CurrentTime>
<param name=zone value=GMT>
</servlet>  first and then the rest two...the param name =zone throughout 
shows the value as GMT...


(41)  3rd paragraph under the heading "implements";
The end of the second sentence reads:

  ... or given through multiple import directives.

It should read:

  ... or given through multiple implements directives.


(45)  paragraph 5, first sentence.;
The first sentence reads:

   Parameters can be passed to a bean as a list using a <PARAM> tags ...

The word "a" before the <PARAM> tag should be removed.

   Parameters can be passed to a bean as a list using <PARAM> tags ...


?84?  3rd Paragraph - "Each access to a servlet....";
I am having a bit of trouble with the following information:

"Each access to a servlet can have any number of request parameters 
associated with it."

I have a substantially large form with a a large number of 
parameters. All of this data is required for the servlet to process into 
XML data.

I am calling my servlet from an HTML page as follows:
<FORM METHOD=GET ACTION="..\servlets\ECreditServlet">

It appears that the query string is being truncated at 2048 
characters. The statement in the book would appear to be bit 
misleading. I am using JDeveloper and testing/debugging my form/servlet 
using JDeveloper's included web server. Is this a limitation of this 
development software?

How can I handle a query string longer than 2048 chars?


{112}  Example 4-18;
The MultipartRequest class will not handle forms that have multi-select 
elements.  All those element will be the last value selected no matter what 
the user selects if the MultipartRequest is used as is. The value in the 
parameters Hashtable should be set to a Vector so that all the selected 
items a user selects in a multi-select element are stored.


{112}  MultipartReqeuest class;
I think the verion of MultipartRequest.getParameter(String name) in 
cos-23jan2001.zip download has a bug in it.

   public String getParameter(String name) {
     try {
       Vector values = (Vector)parameters.get(name);
       if (values == null || values.size() == 0) {
         return null;
       }
       String value = (String)values.elementAt(values.size() - 1);

//  I think it should include the following statement to achieve the
//  desired result.
       if (value.equals("")) return null;


       return value;
     }
     catch (Exception e) {
       return null;
     }
   }


[130]  Let's look...;
htmkKona is apparently no longer available for free evaluation.


[220] About the Security (Chapter 08), there's nothing to show me how for 
example to set first and retrieve after Customers username and password.

The only thing that has been shown is a very poor hashtable inside a 
servlet not always well understood. I think that it'd be better to give 
examples for all the book is talking about.

The author said on the 8th chapter, that it's easy to make servlet that 
looks about user authentification (CustomAuth.java file) and he says that 
someone can change the hashtable with another mechanism like an external 
file or database. I'd like to know how.


[289-291]  The entire class;
I have tried to use your HttpMessage class to POST
data to a URL that is not a servlet, but rather
a PERL cgi script.  I cannot get this to work,
for some reason it is ignoring the name=value
pairs sent in the request.  The response that is
sent back is correct, except that it doesnt contain
the name value pairs.

The get methods contained in the class work well,
however it is the POST methods that I need to use.