I don’t know if it could help in your case (java) but there’s a machine instruction for count leading zeros on x86 platform - LZCNT https://en.m.wikipedia.org/

I don’t know if it could help in your case (java) but there’s a machine instruction for count leading zeros on x86 platform - LZCNT https://en.m.wikipedia.org/wiki/X86_Bit_manipulation_instruction_set https://en.m.wikipedia.org/wiki/X86_Bit_manipulation_instruc... - i found out about this randomly years ago when i was doing some interfacing with a microcontroller from python and my solution was horrifically slow. To exploit this i had to use cython from python to define a c function which used a gcc compiler intrinsic to allow me to write the asm instruction inline. It turned out about 7 lines of code so it wasn’t as bad as it sounds. In your case, you’d need to use JNI i suppose so it might not be any less code but it should at least be a lot faster if that matters.