Re: [Wrapper-user] JVM hang - Xms / Xmx

[Leif M. <le...@ta...>]

Paul,

Paul Casanova wrote:

>Yep - looks like pushing for a 1.4.x upgrade is the way to go.
>  
>
The bug states that the problem was added in 1.4.0 and then fixed in 
1.4.1 so I am
not sure it is the exact same problem.   The bug does state that the JVM 
starts leaking
memory until it finally crashes.  That does sound like what you saw below.

>Our app is a government GIS roads mapping tool for an Australian state
>(that's as much as I can say).  On startup it loads all the data relating
>to each layer of the map (eg freeways / local raods / railway lines etc
>etc) into memory so that they are all there ready for 300+ users to turn
>on/off whichever layer(s) they want - when they want.
>
>I have a feeling that some of the problems with our app center around the
>printing method used.  When the app was developed (around 5 years ago) Java
>printing was slow and problematic (according to code comments) and so the
>app generates a postscript or HPGL file using an OS installed print driver,
>then Java calls the Windows print command to send the file to the user's
>network printer.  Since setting the min/max RAM to different values I've
>been able to get some more pieces to the puzzle when the app crashes.  A
>couple of days ago someone ran a plot (print) and the system appeared to
>get into an infinite loop.  The Windows CPU time for the Java process kept
>ticking over (second for second) - although CPU for the process was only
>6-7% (which indicates that it's a complicated loop - possibly between the
>client and server - there was no network activity between the app server
>and the database server which have a dedicated network card).  However, RAM
>for the Java process steadily increased towards the maximum from about
>1300MB when I first saw it to 1730MB before the client requested a restart.
>I wanted to let it go till it crashed, but the client comes first.
>
>The app was initially written to transfer files from the server to the
>user's PC via FTP (yuck!), which I've scrapped and now just uses Tomcat
>(which was in use for another component of the app anyway).
>
>I'm thinking that the whole approach to printing needs to be overhauled,
>and I've read somewhere that 1.4.x has a new print api.  Any ideas /
>pointers / suggestions (from anyone)?
>
>Has any reader had experience with network printing from Java?  Any
>feedback would be greatly appreciated (as always).
>  
>
I have not had any experience with Java printing.  But a quick search 
returned this:
http://www.javaworld.com/javaworld/jw-10-2000/jw-1020-print.html
It is part 1 in a multi part series.  Links to additional parts are at 
the bottom of the page.

Here is the JSR on the Unified Print API: 
http://www.jcp.org/en/jsr/detail?id=6

Cheers,
Leif