I have some classes that are designed such that the subclass
implementations of foo() *must* call the super class implementation of
foo().
What is the best way of forcing this? I read somewhere that this is

  Im not sure if this was pondered before or not. But why wouldnt you
have the Collection classes be observable, i.e. you can attach
listeners to them that listen to a state change in the collection (add,
remove, etc). Wouldnt that make sense?

regards:
My program logic is following:
http://www.wretch.cc/album/show.php?i=otp&b=1&f=1114017894&p=4
from Step1 to Step4

I switched the default to Turkish on a Windows XP computer and found that
the default character encoding in our Java applet is still the same as with
US English - Cp1252.  I tested using both the system property
"File.encoding" and with OutputStreamWriter.getEncoding().

As a programmer, I don't like the JSTL concept of programming with
tags.
I would prefer the opposite concept: creating HTML with a program,
avoiding tags.

I follow to code the tutorial from JavaWorld but received the following
error:
import java.io.StringWriter;
import org.apache.velocity.app.VelocityEngine;

I'm trying to deploy a new war with tomcat but I'll have the following
exception although the j2ee.jar is in the lib directory. Have anyone
some suggestion?
java.lang.NoSuchMethodError:

I have a class called P and 3 classes X, Y, Z that extend P. In each of
the "child" classes, I have a static array of stuff:
abstract class P {
 static String getValue(int i) {

I have stumbled across something, which seems to be of ambuiguity.
Recently I decoded the URI of a servlet request.
At first I could not get the expected result. The umlauts äüö would
not show up correctly, which made me wonder why.

Hi all....
I am using J2ME Wireless Toolkit 2.2 and always when I call
(new Date()).getTime()
I get the same value. Is this a bug or... ?

I've got a weird bug which I'm trying to characterise. Essentially I'm
calling HttpServletRequest.getRequestURL(). On my development machines
this works fine, but on one of my customer's production machines it
returns 'http://whatever' even when the request was an https

Here's the problem I'm having.  I'm using a servlet to post an XML
document to a server, in turn that server will return a string
representation of an XML document.  I'm using Xerces as my parser but
it seems to me anyways that Xerces can't parse a string representation

request.getRemoteUser() returns null, therefore, authentication has
not been enabled.
I want to be able to get hold of the Windows 2000 login id of the
person invoking my JSP in their web browser. Given that the version of

I'm eager to read the book Thinking in Java, by Bruce Eckler. Unfortunately,
i've spent quite some hours trying to get the code from chapter 3 to run. I
found several "solutions" everywhere on the net (i've also gone through the
steps given on his own website, and read the info ...

Recently I've been getting the following message when I visit different
sites:  "Internet Explorer can not open this helper application for
dtdp://748/331/1/jgen44.cjt1.net/HTM/704/0/javasiterequest.asp?LV=60008DC=453&NFD&IW=7208JH=300&ORD=1111355390281?&.
The protocol specified in ...