I assumed they were talking about tagged fixnums, which have primitive-like performance but can still be treated like objects. https://blogs.oracle.com/jrose/en

I assumed they were talking about tagged fixnums, which have primitive-like performance but can still be treated like objects. https://blogs.oracle.com/jrose/entry/fixnums_in_the_vm https://blogs.oracle.com/jrose/entry/fixnums_in_the_vm