Large number of classes loaded in Jruby on rails app on tomcat


We have a jruby on rails application in tomcat.
Tomcat 6.0.26
Jruby 1.5.5
Rails version 2.3.5

We ran a load test of 100 users on the same during which the memory
utilization went very high. We monitored the application using
jvisualvm. We noticed that there were huge number of classes loaded.
Whenever new classes were loaded huge CPU spikes were observed.
I have attached an image of jvisualvm output depicting the same.

We found a particular issue in jruby :

Is this issue the same? and should we downgrade to jruby 1.5.2 since 1.6
is not yet in production?