Jruby/rack stack dumps without reference to my code

Rails
1

I get a stack dump in jruby,

it will say: org.jruby.exceptions.RaiseException: (NoMethodError)
undefined method `log’ for nil:NilClass

and then print out a lengthy stack dump. None of the source code lines
given however come from any of my code so I am not sure how to figure
out what is causing the dump or how to change the stack dump.

2

On 2 May 2012 17:00, Jedrin [email protected] wrote:

I get a stack dump in jruby,

it will say: org.jruby.exceptions.RaiseException: (NoMethodError)
undefined method `log’ for nil:NilClass

and then print out a lengthy stack dump. None of the source code lines
given however come from any of my code so I am not sure how to figure
out what is causing the dump or how to change the stack dump.

Tell us what you do to generate the error and post the full error text
and the stack dump.

Colin

3

Here is a typical stack dump I get. It’s looking for a log method on a
nil class. none of it is in my code.

This is a sinatra app. Sinatra seems to not do a good job of tracing
compared to rails is my experience thus far

Application Error
org.jruby.exceptions.RaiseException: (NoMethodError) undefined method
log' for nil:NilClass at ServletLog.write(file:c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/ jruby-rac k-1.1.1/lib/jruby-rack-1.1.1.jar!/jruby/rack/servlet_log.rb:18) at CommonLogger.log(c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/ rack-1.3.1/lib /rack/commonlogger.rb:39) at CommonLogger.call(c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/ rack-1.3.1/li b/rack/commonlogger.rb:22) at org.jruby.RubyProc.call(org/jruby/RubyProc.java:270) at org.jruby.RubyProc.call(org/jruby/RubyProc.java:220) at BodyProxy.close(c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/ rack-1.3.1/lib/ rack/body_proxy.rb:16) at Response.write_body(file:c:/jruby-1.6.7/lib/ruby/gems/1.8/ gems/jruby- rack-1.1.1/lib/jruby-rack-1.1.1.jar!/jruby/rack/response.rb:111) at Response.respond(file:c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/ jruby-rac k-1.1.1/lib/jruby-rack-1.1.1.jar!/jruby/rack/response.rb:50) org.jruby.exceptions.RaiseException: (NoMethodError) undefined methodlog’ for
nil:NilClass
at ServletLog.write(file:c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/
jruby-rac
k-1.1.1/lib/jruby-rack-1.1.1.jar!/jruby/rack/servlet_log.rb:18)
at CommonLogger.log(c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/
rack-1.3.1/lib
/rack/commonlogger.rb:39)
at CommonLogger.call(c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/
rack-1.3.1/li
b/rack/commonlogger.rb:22)
at org.jruby.RubyProc.call(org/jruby/RubyProc.java:270)
at org.jruby.RubyProc.call(org/jruby/RubyProc.java:220)
at BodyProxy.close(c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/
rack-1.3.1/lib/
rack/body_proxy.rb:16)
at Response.write_body(file:c:/jruby-1.6.7/lib/ruby/gems/1.8/
gems/jruby-
rack-1.1.1/lib/jruby-rack-1.1.1.jar!/jruby/rack/response.rb:111)
at Response.respond(file:c:/jruby-1.6.7/lib/ruby/gems/1.8/gems/
jruby-rac
k-1.1.1/lib/jruby-rack-1.1.1.jar!/jruby/rack/response.rb:50)

4

I am also using sinatra with this thing called trinidad which is some
kind of web server. When I use web brick I seem to not have soany
problems in this regard. I am not sure why they wanted me to use
trinidad

5

On 2 May 2012 17:00, Jedrin [email protected] wrote:

I get a stack dump in jruby,

it will say: org.jruby.exceptions.RaiseException: (NoMethodError)
undefined method `log’ for nil:NilClass

and then print out a lengthy stack dump. None of the source code lines
given however come from any of my code so I am not sure how to figure
out what is causing the dump or how to change the stack dump.

You may well have a variable that you expect to be set, that is actually
nil. When some other code then comes to use that variable later on, it
is
trying to call the log method on nil. The actual line that is setting
the
variable to nil isn’t in the stack trace because it didn’t throw an
error.
I’d check your code carefully for anything that might be set to nil.
Maybe
use a debugger to step through the code and check the values of
everything.

Of course, it could be nothing to do with that! :slight_smile:

Jeremy W.