Indeed it must be so -- at least it would be very strange to have a thread-unsafe static method where the documentation doesn't spell out how to use it safely[1

Indeed it must be so -- at least it would be very strange to have a thread-unsafe static method where the documentation doesn't spell out how to use it safely[1]. Even in that case it would be a weird thing to even have a thread-unsafe static method (except accidentally, of course). [1] The JDK documentation is pretty good on spelling out such caveats, IME.