The current j2se and hotspot client are built with -xarch=v8, the hotspot server with -xarch=x8plus.

Seems like we all should be using -xarch=v8plus.

-xarch=v8 is for SPARC V8 based machines like the old SPARCstation 10 machines.
-xarch-v8plus is for UltraSPARC chip architecture machines