In windows, I believe requires the registry to be pointing to the
correct JVM and for the appropriate Java.exe to be first on the path
somewhere and for an appropriate SET classpath.

I see I've mislead you.  Sorry.  I meant that you should (IMO) use explicit DLL
loading rather than relying on the primitive and inflexible (%Path% dependent)
stuff which is hard-coded into the stub lib.  It's only a matter of a couple of
extra lines of code (well, maybe half a dozen) and insulates you from all sorts
of hidden nastiness.  Respect the D in DLL and it'll be your friend ;-)

Anyway, here's some example code that I posted a couple of weeks ago.  It lacks
error checking, but should provide useful pointers (or do I mean references?
;-)

I'm not sure what the mingw equivalent of the first two lines would be, but
since dynamically loading DLLs is /the/ central operation of any Windows
program, there must be an equivalent.  With luck the code'll work as-is.  I
repeat that you shouldn't need any special (to JNI) -l or -L flags for this to
work -- you are using DLLs not static libs, so the linker has nothing to do.

   -- chris

=======================
#define WIN32_LEAN_AND_MEAN
#include <windows.h>

#include <jni.h>

typedef __declspec(dllimport) jint (__stdcall * CreateJavaVMFunc)(
                       JavaVM**,
                       void**,
                       void*);

// called with the full path to the JVM dll as its only parameter
int
main(int argc, char** argv)
{
   // get lib entrypoint
   HINSTANCE lib = LoadLibrary(argv[1]);
   CreateJavaVMFunc createJavaVM = (CreateJavaVMFunc)GetProcAddress(
                             lib,
                             "JNI_CreateJavaVM");

   // start JVM
   JavaVMInitArgs initArgs;
   JavaVMOption options[2] = { { "-verbose:jni" } , { "-Xcheck:jni" } };
   initArgs.version = JNI_VERSION_1_2;
   initArgs.nOptions = 0;
   initArgs.options = options;
   initArgs.ignoreUnrecognized = true;
   JNIEnv *jniEnv;
   JavaVM *javaVM;
   createJavaVM(&javaVM, (void**)&jniEnv, &initArgs);

........
=======================

Excellent question.  Far too many people here seem to get
caught up in the 'interestingness of an absraction/question'
rather than asking if the question 'makes any sense'.

What use is that?  Are you saying you can get your application
to work on '40% of the memory available on a 64 Meg machine'?

Better, you could use a small Java program that asks the *user* how
much RAM they want to dedicate to the application and call an
actively generated JNLP specifying that amount.

(..and have we discussed that indent you use?)