[mapserver] Java VM Crashes using the Mapscript API

[Christian Schroeder]

Hello Mario,

thank you for this tip,
I've read about this problem somewhere else and tagged my whole method 
which uses the mapserver calls as "synchronized", but it did'n help.
I will try it the way you supposed to and hope it will not crash then..

Thank you,

Christian,
Germany

Mario Basa schrieb:

>Hello,
>
>I used to get these problems until I synchronized the cleass doing the
>map operations (synchronize(this)). I also placed tons of try...catch
>hoping that the exceptions can be caught before it brings down tomcat.
>
>I am using 4.6.0 and it has been very stable for me so far, although I
>haven't put too much stress on the servlet yet.
>
>mario.
>yokohama,japan.
>
>
>On 6/22/05, Sean Gillies <sgillies at frii.com> wrote:
>  
>
>>I'm forwarding this to the users list. Hopefully, Umberto will be able
>>to provide some insight.
>>
>>cheers,
>>Sean
>>
>>On Jun 16, 2005, at 5:08 PM, Christian Schröder wrote:
>>
>>    
>>
>>>Dear Mr. Gillies,
>>>
>>>some weeks ago me and Florian Pepping contacted you because we had
>>>problems using the Java Mapscript API. Thanks to you we could solve
>>>these problems :-)
>>>
>>>Now we got our program doing what it's supposed to do but there is
>>>still a big problem left which we were not able to solve yet:
>>>We created a simple servlet which is created inside a Tomcat 5.0
>>>Webserver. This servlet created a map image (png/jpg) and displays
>>>some specified objects on the map. (We use it for location based
>>>services --> "show me the position of the next printer").
>>>After an irregular number of calls of our servlet which uses the Java
>>>Mapscript API the complete Java VM and with it the Tomcat crashes. I
>>>attached the error report below. The program works properly for a
>>>number of calls (between 5 and 1000 :-) ) and after that it crashes.
>>>We have tried several versions of the mapserver (4.4.1, 4.4.2, 4.2.4,
>>>4.6.1 RC1) and compiled the Java Mapscript Module with JDK 1.4.2 and
>>>1.5.0. We also configured mapserver using the --with-threads option,
>>>but all this did not help. By the way the mapserv cgi-module works
>>>properly.
>>>
>>>Do you have an idea for this?
>>>
>>>Thanks for your anxiety
>>>
>>>Christian & Florian
>>>University of Paderborn, Germany
>>>
>>>
>>>-------------------------------------------------------------------
>>>
>>>JavaMapscriptLoader: mapscript native library has been loaded.
>>> * mapscript native library loaded *
>>>
>>>An unexpected exception has been detected in native code outside the
>>>VM.
>>>Unexpected Signal : 11 occurred at PC=0x3338268
>>>Function=delete_classObj+0x8
>>>Library=/usr/lib/libmapscript.so
>>>
>>>Current Java thread:
>>>        at edu.umn.gis.mapscript.mapscriptJNI.delete_classObj(Native
>>>Method)
>>>        at edu.umn.gis.mapscript.classObj.delete(classObj.java:32)
>>>        at edu.umn.gis.mapscript.classObj.finalize(classObj.java:26)
>>>        at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
>>>        at java.lang.ref.Finalizer.runFinalizer(Finalizer.java:83)
>>>        at java.lang.ref.Finalizer.access$100(Finalizer.java:14)
>>>        at
>>>java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:160)
>>>
>>>Dynamic libraries:
>>>Can not get information for pid = 10558
>>>
>>>Heap at VM Abort:
>>>Heap
>>> def new generation   total 1152K, used 135K [0x08ae0000, 0x08c20000,
>>>0x08fc0000)
>>>  eden space 1024K,   0% used [0x08ae0000, 0x08ae4078, 0x08be0000)
>>>  from space 128K, 100% used [0x08c00000, 0x08c20000, 0x08c20000)
>>>  to   space 128K,   0% used [0x08be0000, 0x08be0000, 0x08c00000)
>>> tenured generation   total 15048K, used 13624K [0x08fc0000,
>>>0x09e72000,
>>>0x0cae0000)
>>>   the space 15048K,  90% used [0x08fc0000, 0x09d0e1c0, 0x09d0e200,
>>>0x09e72000)
>>> compacting perm gen  total 18432K, used 18373K [0x0cae0000,
>>>0x0dce0000,
>>>0x10ae0000)
>>>   the space 18432K,  99% used [0x0cae0000, 0x0dcd1618, 0x0dcd1800,
>>>0x0dce0000)
>>>
>>>Local Time = Tue Jun 14 15:32:19 2005
>>>Elapsed Time = 246
>>>#
>>># The exception above was detected in native code outside the VM
>>>#
>>># Java VM: Java HotSpot(TM) Client VM (1.4.2_08-b03 mixed mode)
>>>#
>>># An error report file has been saved as /tmp/hs_err_pid10558.log.
>>># Please refer to the file for further information.
>>>#
>>>
>>>-------------------------------------------------------------------
>>>
>>>On Mar 22, 2005, at 12:02 PM, Florian Pepping wrote:
>>>
>>>      
>>>
>>>>Dear Mr. Gillies,
>>>>
>>>>I'm a student of the University of Paderborn in Germany and member of
>>>> the project group "Location Based Services for Wireless Devices". In
>>>> this project we try to position laptops and other WLAN-enabled
>>>>devices  using the signal strength of the WLAN. According to their
>>>>position, we  want to offer location based services to the persons
>>>>using the devices  (where I am; where's the next printer; is there a
>>>>friend nearby)
>>>>
>>>>In order to do this, we want to use your mapserver and the Java
>>>>Mapscript API to generate maps according to the actual position and
>>>>situation. We like to customize the map of our building and add
>>>>points, lines and so on.
>>>>
>>>>We have been able to compile the whole mapserver and the Java
>>>>Mapscript API. A small Java example also works, which presents an
>>>>unchanged map of our building.
>>>>
>>>>[...]
>>>>        
>>>>
>
>
>  
>