Hi, I am having trouble figuring out why this is giving a null pointer
exception:
[code]
java.lang.NullPointerException

I'd like to use a StringTokenizer with a "delim" formed by all the
characters that don't verify the condition isLetter(). Can anyone give me a
clue on how to do this? is there anyway to make a String with all characters
appearing once and only once?

I have installed Tomcat at home to learn JSP. I am trying to use the useBean
action element.
I get the following error report.
org.apache.jasper.JasperException: Unable to compile class for JSP

Does anyone know
how can I close internal frame with Alt+F4 command (windows closing)

For installing java applications is java Webstart a substitute for making an
installer using, for example, InstallAnywhere ?
patrick

Hello, I'm getting a ClassCastException and I'm not sure why. The code
for the casting -  op1 = ((Integer)newStack.pop()).intValue(); -  as I
understand it, is supposed to cast the object returned by pop to an
Integer object and then the actual primitive value is grabbed by

Can Eclipse plug-ins be used in Java projects?
I'm developing an application that requires SQL code to be displayed to end
user and it would be nice to incorporate one of the many open source SQL
plug-ins for Eclipse to format the SQL code in a easy to read manner.  Is

Very shortly I may have to build a java web application for Tomcat which has
a 30 day evaluation period built into it. Just the standard thing - you can
use it for 30 days, and once this has expired, the software becomes
unuseable until the user buys a key to fully activate the ...

I am writing a chat client - the client needs to check the socket for data
every, say 2 seconds (using timer).
The client has no problems reading output from the server, however if there
has been no data written since the last check, then socketinput.readLine

I'm trying to build a servlet that "hides" a button from the user
between certain hours of certain (non-sequentsial) days.  I have taken
JSP classes and have a big ol' book sitting here, but have no idea
where to start with this one.  Can someone please point me in the

I'm stumped :-(
I can't create an algorithm for this ticklish problem, nor think of any
pseudocode; yet i know exactly what to do in my head.  I can't even work it
out on a calculator, let alone find a suitable solution i could code into a

Platform: Windows 2000
JDK 1.3.1_09
Java newbie here, is there any way of displaying methods that
are in a .class file?  I have a compiled object and would like

Can anybody help me to find a library in java to work with tiff?. I
need to do some operations on the tiff, like resize, negative, put
ellipses, circles and annotations over the image. I need an open
source library or a low cost one.

What is the fastest way of combining x byte arrays of variable length into a
single new byte array?
I'm trying to download chunks off of a Socket, and return them as a single
byte array. At the moment I store all the chunks in a Vector, calculate the

Am working on a small http - cache program &
Have some problems with Java & URL:s.
1) How can I check the file lastModified() - date through its URL, without
having to download the file?