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Comment by tempguy9999 | Hacker News Reader

Interesting. First I've heard of it. Well I guess if you can ensure bounded space by limited allocaton, then simply shove manually 'freed' stuff back on a free list, you could do that, sure.

But a quick google gets https://openjdk.java.net/jeps/318 which does say

  Non-Goals
  It is not a goal to introduce manual memory 
  management features to Java language and/or JVM...

but it doesn't say you can't or shouldn't. Game on then.

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Sure, if all your objects are mutable, then that can work, but a lot of stuff in core libraries are not, and you can’t control those allocations, short of not using them. There is also sun.misc.Unsafe, which has freeMemory, but first of all, I don’t know if that works for arbitrary addresses, or just ones previously allocated from the allocateMemory method, and anyways, I don’t think there’s a reliable way to get the address of an arbitrary object in the first place. But to add both of those pieces of functionality should be a pretty small patch to the jvm code anyways, so if someone were really motivated, it may not be all that much work anyways.

> and you can’t control those allocations

You're totally right. Rather stupidly I hadn't thought of that.

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