There are couple issues regarding the synchronization behavior of class loading. The fix of 6365597 will partially solve that and it is important to understand the impact of the fix and also how the outside people to use classloader. This RFE will try to set up couple performance counters which try to identify:
1. How frequently the class loader locks are contended?
2. When JVM_FoundLoadedClass, JVM_DefineClass and etc are called from J2SE side, does the caller thread hold some classloader lock?