If you want vendor-neutral, equally inefficient code on all platforms, you know where to find Java.
Let's not inadvertently sell Perl short. Perl
is an example of a vendor neutral language, and ActiveState's port of the language to Windows seems full-featured to me.
On the other hand, Java can't be vendor-neutral, because it is owned by Sun Microsystems and Sun is one of the largest hardware/software vendors in the world. Even if Sun were to say that it does not use its ownership of Java to promote their own products I would not believe them.