Profiling application on JamVm

Hello,

    I have deployed web application with Jam VM and gnu classpath,
After deploying web application in Jetty , It grabs 20+ MB Residential 
memory
Need to why these much memory required by application / Virtual Machine.

For need for profiling , Using JProfiler have to add two arguments while 
invoking container

Adding two arguments in invoking Jetty
-Xrunjprofiler:port=8849 -Xbootclasspath/a:/sig/jprofiler6/bin/agent.jar

JamVm does not accept -Xrunjprofiler:port=8849 as an argument while it 
works fine with JVM distribution
exported required library(ibjprofiler.so) path by jprofiler

I m not getting why JamVm does not accept -Xrunjprofiler:port=8849 argument
Is there any profiling tool which is preferable and working on jamvm

class path configured with no arguments (all components taken)

regards,
Siddharth