High CPU usage on sun.reflect.Generated* class loads by log4j

We have been running some performance tests to prepare our OSGi bundle (running in Apache Karaf) for production.

Just to give some background about our OSGi bundle, we converted an existing Spring application into an OSGi bundle with all the current dependencies packaged into the bundle as an uber artifact.

When we run >= 500 TPS (each of these calls results in a http call made via a library) we run into this high CPU usage spikes reaching up to 100% CPU. Please see the image attached, the spikes in the image are 100% CPU usage while the average is about 40%. Also see the CPU sampler image which points to org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation

Is there an existing bug/documentation that already captures this?

We don't see this behavior when we run the same app in standalone JVM.