As the comment you replied to indicates, both of those APIs perform bounds-checking. In certain tight loops, this can add up to quite a bit of overhead [1]. How

As the comment you replied to indicates, both of those APIs perform bounds-checking. In certain tight loops, this can add up to quite a bit of overhead [1]. However, it's not documented, but if you really know what you are doing you can convince the JIT to elide the bounds checks for MemorySegments [2]. [1] https://mail.openjdk.org/pipermail/panama-dev/2023-July/019363.html https://mail.openjdk.org/pipermail/panama-dev/2023-July/0193... [2] https://mail.openjdk.org/pipermail/panama-dev/2023-July/019487.html https://mail.openjdk.org/pipermail/panama-dev/2023-July/0194...