Re: Realtime class update

From:

"Andrew Thompson" <u32984@uwe>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 26 Jul 2007 11:06:42 GMT

Message-ID:

<75bef3f442da6@uwe>

O.L. wrote:
...

I have a standalone Java application which has to be started and then
not stopped for weeks.
Is it possible to rebuild some of its classes and reload then inside
the running JVM, to be able to modify its behaviour without having to
stop and restart the application ?

Not that I know of, but happy to be surpised.

I heard about ClassLoader and its caching functionnality ... ?

'aggressively' is how I would describe CL caching.

Thank you if you have any info :)

Have you considered web start* for this application?

Web start offers the DownloadService** that can check if
Jar's are updated.

This would still leave it up to the application to
a) check occasionally for upates
b) update the necesary parts or Jar archives.
c) inform the user they need to RESTART THE APP.

c) might not be necessary if you find some really
clever way to update the classes in the current
ClassLoader.

** <http://java.sun.com/javase/6/docs/jre/api/javaws/jnlp/javax/jnlp/DownloadService.html

* Gee, color everybody 'surprised'!

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

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