Project Valhalla, Explained: How a Decade of Work Arrives in JDK 28

> is it necessary for the performance boost and de-fluffing the objects? Yes. The one part of the JVM GC that can't run concurrently is heap compaction; objects that can be moved by copying and then deleting would be a huge help for that. And it would be awkward to say the object has an identity but can't be wait/notify'd, at which point you need somewhere for the monitor to go. > Does this happen in actuality? One would assume the allocator tries to put stuff sequentially on the heap? Yes. O…

There’s nothing wrong with having non-normalized representations, that’s why there is equals(). For example, you might have a value class for representing (limited-precision) fractions using two longs internally, for the numerator and denominator. For efficiency trade-off reasons, you don’t want to always shorten the fraction. But now client code can distinguish 2/3 from 4/6 using ==. Scenarios of that sort are conceivable where this actually leaks sensitive information. In any case, it create…

> The whole attitude and process around this and the other topics gives me very little faith that Java can be steered in a sensible direction here. I agree. The stewardship of Java seems rather lacking - particularly when compared to that of .net, where MS etc. mostly seemed to make the correct decisions from the start. Does Java even have any value or mindshare at Oracle nowadays? The company seems to be a datacentre/compute business at this point, with appendiges for its legacy activities an…

Value types are a concept very far away from the "magic black box organism" school of OOP thinking. It's not a novel way of doing classic OOP (does anyone still do that?), it's a way for a language born in OOP ideology get one step further into the post-OOP world.