Re: Java Web Start misbehaving

From:
"Andrew Thompson" <u32984@uwe>
Newsgroups:
comp.lang.java.help
Date:
Fri, 20 Apr 2007 09:19:23 GMT
Message-ID:
<70fa72ee9436e@uwe>
ZenFire wrote:

First off, thanks fo rthe assistance.


You can better express your thanks, by *reading*
(and following the advice contained in) the link I put
upthread. Here it is again..
<http://www.physci.org/codes/javafaq.html#toppost>

I uploaded the modified version here
http://wwwhome.cs.utwente.nl/~kock/exp/ExperimentTrilogy2.jnlp


OK - I'll give this one a try..

I should have mentioned before that the original jnlp file was
generated by netbeans.


I kind of figured that. ;-)

...You might have noticed that after the
dtd file turned out not to exist. The only thing I added manually
was the spec attribute.

As for the many other changes you made, I'm surprised at
how short and readable the jnlp file can be when you get
rid of all that exces stuff.


IDE's can add a lot of unnecessary dross to code.

..I assumed the javaws.jar was there
to provide the web start sevices.


the javaws.jar comes standard with any JRE that
understands web start - no need to include it in the
download.

..It contains the packages
com.sun.javaws (and assorted suffices) and javax.jnlp


Yep. I am familiar with it.

Anyway, as you can see by following that link, it still does not
work. Yesterday I made the application start out of an applet.


When you say 'application', it makes me pause.
In Java parlance, something is either an application
*or* an applet (though you might have a combined
application/applet). It is perhaps important to underline
the distinction, since applets do not have an
application-desc element in the JNLP, but an
*applet-desc* element. If this project is completely
and only an applet - the JNLP needs to say as much.

The fact that it works shows the libraries I'm using aren't
violating sandbox rules.


Good. I cannot afford to download applications or applets
that require full privileges - at least not from 'some dude
on usenet' that is not yet sure of what is going wrong.
(No offence intended).

..Though if they did, I'm sure I'd get an
error as opposed to nothing.


Yes, you sure would, unless the code is doing something
silly like 'swallowing exceptions', which is quite unnervingly
common.

And now the project has arrived, I can report that I am
getting exception..

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javazoom.spi.mpeg.sampled.file.MpegAudioFileReader.getAudioInputStream
(MpegAudioFileReader.java:498)
    at javax.sound.sampled.AudioSystem.getAudioInputStream(Unknown Source)
    at utwente.ewi.kock.phd.TopWindow.loadAudioMP3(TopWindow.java:512)
...

..which brings me back to the fact you said you were
getting no excpetions. Why? Do you have the Java
console configured to pop-up automatically on launch
of a JWS app.? It is possible to configure the Java
Control Panel to do that - and quite vital for any JWS
development.

--
Andrew Thompson
http://www.athompson.info/andrew/

Message posted via http://www.javakb.com

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