GeoServer 1.7.5 critical WMS patch

The latest stable GeoServer version, 1.7.5, was released with a small but critical bug that slows down rendering when a very small polygon or a line is displayed at a high zoom level (so that the displayed area is a very small fraction of the
whole). The slowdown increases as one zooms in, and eventually may lead the Java Virtual Machine to crash.
The bug also makes for non optimal rendering of cased roads (the typical highway display).

The issue is actually due to a Sun Java bug, but happily we have a workaround for it. If you find you’re affected by this problem, follow these simple instructions:

  • stop GeoServer
  • download this patch jar and save it under geoserver/WEB-INF/lib
  • restart GeoServer

Voilà, bug gone.

We want to thank Stefan Ziegler for the quick bug report and the other users that reminded us of how important this patch is.


  1. Joshua M. Thompson
    Posted July 7, 2009 at 10:55 am | Permalink

    A couple things:

    1. In addition to hard locking this bug also has the nasty habit of eating up all available memory, eventually crashing tomcat or even the machine it’s on (that’s how we found the bug…), so it’s probably a good idea for everyone running 1.7.5 to install this even if they aren’t hitting the bug just yet.

    2. The file needs to be renamed after you download it, but this wasn’t mentioned in the post. Rename gt-api-256.jar to gt-api-2.5.6.jar. Otherwise you won’t actually get the fix.

    Other than that, works like a charm! Not only does zooming all the way into my vector base map no longer kill the server, it’s also noticeably faster. Kudos!

  2. Andrea Aime
    Posted July 7, 2009 at 11:03 am | Permalink

    Jushua, thanks for the report. I’ve modified the link so that it points to a jar that does not need to be renamed anymore.

  3. Chris
    Posted July 13, 2009 at 4:25 pm | Permalink

    thank you! I spos the great gazoogle (or even this blog) could have spared me days in pulling my hair out

  4. Posted July 18, 2009 at 12:49 am | Permalink

    Thank you very much for sharing this blog..

  5. Ivan
    Posted July 20, 2009 at 7:35 pm | Permalink

    Can we assume that the patch is now pre-included in the current ‘stable’ download ?

  6. Andrea Aime
    Posted July 21, 2009 at 1:07 am | Permalink

    Ivan, nope, the release binaries have not been updated. That would take a few hours and so far no one had that amount of extra time, so we’re waiting for the next stable release (1.7.6).

    If you have extra resources and want to contribute to GeoServer some way (release management for example) please drop by the GeoServer dev channel and let us know, that would be very welcomed 🙂

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