ClassDescriptor Contract describing the information Hibernate needs in terms of instrumenting a class, either via ant task or dynamic classloader. 
ClassFilter Used to determine whether a class should be instrumented. 
FieldFilter Used to determine whether a field reference should be instrumented. 


BasicClassFilter BasicClassFilter provides class filtering based on a series of packages to be included and/or a series of explicit class names to be included. 
ByteCodeHelper A helper for reading byte code from various input sources.