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JVM Crash

J Wallace
Greenhorn

Joined: Jan 30, 2008
Posts: 5
Hi,

I'm running a Java 1.4.2 application on a Red Hat machine that causes the JVM to crash with a SIGSEGV error. -Xms is 64M and -Xmx is 128M. I first thought that the perm gen size was too low since it always has a high percentage (98/99%) when the JVM crashes. After reading more about the perm gen, though, I'm not so sure. Am I looking down the right path by thinking it may be the perm gen size being too low or is the percentage so high just because the JVM will resize it dynamically? When it crashes the perm gen's total size is around 10/11 MB and its usually 99% full.

Below are some snippets of the JVM's output.



...



...



If it's not the perm gen, does anyone have any other suggestions?
Henry Wong
author
Sheriff

Joined: Sep 28, 2004
Posts: 18896
    
  40

A segmentation violation is something that you should never get with Java. Log into bugs.sun.com, and search to see if there is a bug that is similar to what you are encountering. Check for any known work-arounds. If not, then report the bug...

Henry


Books: Java Threads, 3rd Edition, Jini in a Nutshell, and Java Gems (contributor)
Nicholas Jordan
Ranch Hand

Joined: Sep 17, 2006
Posts: 1282
I had some bulky code I wrote recently doing some thinking about an issue in a post and I intentionally left a recursive call such that it would either blow out the stacks or the jvm would have some mighty powerful optomization built in.

It crashed, I set it to a more sane loop construct, it ran - very well.

I suspect the ( what looks to me to be a segmentation violation ) which comes from memory hogging probably, would be better addressed by re-writing the app. Also we have an opportunity for Linux questions in a forum for that purpose.

please re-write the code line that is stretching the window thus:


visit: Linux / UNIX at our facility.


"The differential equations that describe dynamic interactions of power generators are similar to that of the gravitational interplay among celestial bodies, which is chaotic in nature."
J Wallace
Greenhorn

Joined: Jan 30, 2008
Posts: 5
Should I be concerned about the perm gen being at 99% capacity when the JVM crashes?
Henry Wong
author
Sheriff

Joined: Sep 28, 2004
Posts: 18896
    
  40

Originally posted by J Wallace:
Should I be concerned about the perm gen being at 99% capacity when the JVM crashes?


Well, as mentioned, since a seg fault should never happen, the answer is "I don't know". You are basically speculating on a cause for something that should never happen.

Anyway, if you really believe that it is the permanent generation portion of the heap, you can increase it...

-XX:MaxPermSize=256m

This should raise it from the default size of 64 meg.

Henry
 
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subject: JVM Crash