While running few benchmarks vs https://github.com/quarkusio/quarkus-super-heroes/blob/main/README.md

using native image (graal CE) we found OutputBuffer::writeCharacters heap-based code path to be:

• bloated by many not inlined calls: which Graal CE should be blamed since it has a very simple and naive inliner

• an excessive usage of logic to handle the current buffer to be used to write chars into
• zero loop unrolling due to the complexity of the main loop

The same takes can be observed with any recent version of Hotspot (JDK 21) .