Remix clone Hacker News

All allocated objects would have the three least significant bits as 0. Any java object cannot be 'too small' as they all have object headers (more if you need a fully blown synchronized/mutex). So with compressed pointers (up to 32GB Heaps) all objects are aligned but then again, each pointer is 4 bytes only (instead of 8). Overall it's a massive win.

▲

kstrauser 2 days ago | parent [-]

Huh, that’s clever! Do you have to choose that at compile or launch time, or does a program start like that and then “grow” when it uses more than 32GB of heap?

	▲	xxs 2 days ago \| parent [-]
		In Java you have to set max heap somehow - either ergonomics or just -Xmx command line option. Max heap is given (many a reason, and it sets before running the main method), so if you pick under the 32GB it'd auto use compressed pointers (optimize for size - optimize for speed). That option (compressed pointers) can be switched off, of course, via a command line option as well.