> In isolation, this sounds like a description of how HotSpot works, no? First of all, Graal is a compiler that serves as a HotSpot compiler when running as a

> In isolation, this sounds like a description of how HotSpot works, no? First of all, Graal is a compiler that serves as a HotSpot compiler when running as a Java bytecode JIT (HotSpot is the name of OpenJDK's JVM: it includes two compilers, with Graal serving as a third, an interpreter, several GCs and various other runtime features). But yes, HotSpot's default optimizing compiler, called C2, also does speculative optimizations and deoptimizes on "mistakes", but Graal is more general in the sense that its easier to teach it various optimizations for many languages. C2 is very good, but because Graal is believed to be easier to maintain, it may match and surpass it one day (it already surpasses it for some important workloads). Project Metropolis investigates the possibility of eventually making Graal the default optimizing compiler in HotSpot (https://openjdk.java.net/projects/metropolis/ https://openjdk.java.net/projects/metropolis/)