Java native methods issues with SUN JVM (jdk1.5.0_14) and multi-core processors

We are hosting an application on a SUN JVM that handles a lot of XML parsing using Jaxb. Application parses XML tone using JRockit 5, but when using JVM SUN JVM spends most of its time on native methods like java-lang.System.arraycopy, java.lang.String.intern and java.lang.ClassLoader.getPackage ... The processor load is approx. 60% higher when using SUN JVM compared to JRockit.

Even stranger is that when we only run the application server using one core (in WMWare), the problem disappears.

Has anyone experienced the same behavior?

Matthias Arnersten