[hueho]

As far as I understood this is very much intended to be used in multi-threaded code as well. If you are sure that your object won't be called in multiple threads you can just do the simple "if(ref == null)" without locking and it should be reasonably fast - just not constant-foldable by the JVM.

[samus]

The ComputedConstant indeed has to be threadsafe, but the proposal reads as its initializer would be executed on the thread of the caller of get(), and other callers would have to wait until initialization has completed. Indeed very useful for multithreaded programs as well.