Allocation on the JVM: Down the rabbit hole

Re:Allocation on the JVM: Down the rabbit hole by haneefmubarak on Monday July 11, 2016 @07:56PM (#12075710)

So... Why exactly does it need 24 bytes if a long is only 8 bytes (64 bits)?

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Re:Allocation on the JVM: Down the rabbit hole by kaushiks on Monday July 11, 2016 @07:59PM (#12075721)

For the 16 byte (on x86_64) header (markOop, klass *).

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Re:Allocation on the JVM: Down the rabbit hole by jcdavis on Monday July 11, 2016 @08:09PM (#12075770)

The header is only 12 bytes with compressedOops (which most people use), but the long is aligned on an 8 byte boundary so the advantage is wasted here.

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Re:Allocation on the JVM: Down the rabbit hole by alblue on Monday July 11, 2016 @11:27PM (#12076543)

And even if the long wasn't on an aligned boundary, the object itself is. So you either have padding at the start or end of the object.

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