[logback-user] What would cause "java.lang.NoClassDefFoundError: ch/qos/logback/classic/spi/ThrowableProxy" in long running daemon

[Paul Krause]

Seems like overkill. All you need to do is preload the classes you need to log your failures while NFS is still working normally, right?   For example, you could log a test exception as part of your initialization sequence. Once the classes have been loaded into the JVM they won't be evicted. 

Thanks,
Paul

> On Aug 31, 2015, at 11:16, David Roussel <nabble at diroussel.xsmail.com> wrote:
> 
> Hopefully /tmp is local disk?
> 
> Write a bootstrapped that reads the jars off the network, writes them to /tmp, construct a class path then create a classloader and boot your main class. 
> 
> Or you could use the capsule open source project which pretty much does that for you. 
> 
> David
> 
>> On 31 Aug 2015, at 16:03, Fred Toth <ftoth at synernet.com> wrote:
>> 
>> Hi David,
>> 
>> For better or worse, these particular apps are on one of these modern disk systems where EVERYTHING is an NFS mount. Supposed to "just work", you know.
>> 
>> Thanks,
>> Fred
>> 
>>> On 8/31/15 6:55 AM, David Roussel wrote:
>>> Are you storing your jar files on the NFS mounts?
>>> 
>>> Seem like a bad idea if you are.  If a network error causes an exception, and the exception handler calls a class that has not been loaded yet, the class loader will try to load it.
>>> 
>>> The network is unreliable, you must be able to handle network failures.
>>> 
>>> If you are using NFS for ease of deployment, say for batch jobs, there is another way.
>>> 
>>> David
>>> 
>>>> On 30 Aug 2015, at 01:58, Fred Toth <ftoth at synernet.com> wrote:
>>>> 
>>>> Hi,
>>>> 
>>>> We have multiple production processes that run 24 hours a day, 7 days a week. All use slf4j/logback and recently we had several of these (seemingly coincidentally) spew:
>>>> 
>>>> java.lang.NoClassDefFoundError: ch/qos/logback/classic/spi/ThrowableProxy
>>>> 
>>>> These are long running processes where nothing has changed recently. Obviously the logback jars are available, in the right place, etc.
>>>> 
>>>> I'm stumped. There are some hints of some possible system related problem (like missing NFS mount, possibly).
>>>> 
>>>> Does logback dynamically load the above class? Again, this error is out of the blue, from a process that may have been running for days or weeks.
>>>> 
>>>> Any ideas?
>>>> 
>>>> We're using version logback 1.0.13.
>>>> 
>>>> If I google the above, there are some references to "Spring Boot" which we are not using. However, we are using Spring Integration, in case that matters.
>>>> 
>>>> Any ideas?
>>>> 
>>>> Thanks,
>>>> Fred
>>>> 
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