rand(3) isn&#x27;t really the OS&#x27;s concern, it&#x27;s part of POSIX and the C standard which don&#x27;t indeed, but could. Java specifies exactly how java.util.Random should be implemented (LCG from TAOCP with a 48 bit seed), which on the one hand means its well-understood and stable across machines, and on the other hand means it&#x27;s kinda crap and can&#x27;t ever be upgraded.