Hi Hardy, sorry for the late answer, I remember some discussions between us about the coming of an API to help us with threadsafe objects which couldn't use contructor initialization (and hence final fields) but wasn't able to find the API back I spoke about. The javadoc for jsr166y : http://gee.cs.oswego.edu/dl/jsr166/dist/jsr166ydocs/ but the API I was most interested in somehow disappeared and I couldn't remember the name. It is called Fences (at list the article back) and is an extension of jsr166y Quoting part of the javadoc: "With care, a fence may be used to obtain the memory safety effects of final for a field that cannot be declared as final, because its primary initialization cannot be performed in a constructor, in turn because it is used in a framework requiring that all classes have a no-argument constructor. " http://gee.cs.oswego.edu/dl/jsr166/dist/docs/java/util/concurrent/atomic/... the problem is that jsr166y is a preview of the concurrency APIs of Java7, and as such can be backported (there's a jar already you could depend on to make it work on JDK 5 and 6), but the Fences rely on JVM support so they can't be backported: so they are not included in jsr166y. That makes it quite useless for Search and Bean Validation :-( but it's still interesting to read about it as Fences documentation is a good reference for all the pitfalls in design of a "framework requiring that all classes have a no-argument constructor".