More on this. I'm trying this patch :
--- jdk/make/common/shared/Platform.gmk.orig 2010-11-20 19:33:19.000000000 +0100 +++ jdk/make/common/shared/Platform.gmk 2010-11-21 00:33:37.000000000 +0100 @@ -272,6 +272,11 @@ # Darwin builds may be 32-bit or 64-bit data model. ifeq ($(SYSTEM_UNAME), Darwin) + ifeq ($(ARCH), amd64) + ifeq ($(ARCH_DATA_MODEL), 32) + ARCH=i586 + endif + endif ifeq ($(ARCH), i586) 32bits JVM is now correctly built on OS/X 64bits : openjdk version "1.7.0-internal" OpenJDK Runtime Environment (build 1.7.0-internal-henri_2010_11_21_00_48-b00) OpenJDK Server VM (build 20.0-b02, mixed mode)