Can't load jvm.dll in Vista

Question

I have a bizarre problem with JDK1.6.0_03 and Windows Vista. I am trying to compile and run a C program that calls a Java method, using the invocation API. In the past, this worked like a charm, provided I had c:\Program Files\Java\jdk1.6.0_03\jre\bin\client on the PATH.
It no longer works. I get an error message that jvm.dll was not found and that Windows will notify me if it finds a solution to my problem. (I am not holding my breath.)
I then try to load the library manually:
   HINSTANCE h = LoadLibrary("c:\\Program Files\\Java\\jdk1.6.0_03\\jre\\bin\\client\\jvm.dll");
   if (h == NULL)
       printf("Can't load library\n");
       exit(1);
     }I get the exact same error message.
Did something break in Vista, or do I need to look elsewhere for a stupid configuration error?
Thanks,
Cay Horstmann

Answer 1

Just in case some other poor soul gets to this, here is the way to implement the invocation under Windows Vista:
#include <jni.h>
#include <stdlib.h>
#include <windows.h>
typedef jint (JNICALL *CreateJavaVM_t)(JavaVM **, JNIEnv **, JavaVMInitArgs *);
int main()
   JavaVMOption options[2];
   JavaVMInitArgs vm_args;
   JavaVM *jvm;
   JNIEnv *env;
   long status;
   jclass class_Welcome;
   jclass class_String;
   jobjectArray args;
   jmethodID id_main;
   HINSTANCE h1, h2;
   CreateJavaVM_t createJavaVM;
   h1 = LoadLibrary("c:\\Program Files\\Java\\jdk1.6.0_03\\jre\\bin\\msvcr71.dll");
   if (h1 == NULL)
      printf("Can't load library msvcr71.dll\n");
      exit(1);
   h2 = LoadLibrary("c:\\Program Files\\Java\\jdk1.6.0_03\\jre\\bin\\client\\jvm.dll");
   if (h2 == NULL)
      printf("Can't load library jvm.dll\n");
      exit(1);
   options[0].optionString = "-Djava.class.path=.";
   memset(&vm_args, 0, sizeof(vm_args));
   vm_args.version = JNI_VERSION_1_2;
   vm_args.nOptions = 1;
   vm_args.options = options;
   createJavaVM = (CreateJavaVM_t) GetProcAddress(h2, "JNI_CreateJavaVM");
   status = (*createJavaVM)(&jvm, &env, &vm_args);
   if (status == JNI_ERR)
      printf("Error creating VM\n");
      return 1;
   class_Welcome = (*env)->FindClass(env, "Welcome");
   id_main = (*env)->GetStaticMethodID(env, class_Welcome, "main", "([Ljava/lang/String;)V");
   class_String = (*env)->FindClass(env, "java/lang/String");
   args = (*env)->NewObjectArray(env, 0, class_String, NULL);
   (*env)->CallStaticVoidMethod(env, class_Welcome, id_main, args);
   (*jvm)->DestroyJavaVM(jvm);
   return 0;
}Compile with
gcc -g -mno-cygwin -D __int64="long long" -I /cygdrive/c/Program\ Files/Java/jdk1.6.0_03/include/ -I /cygdrive/c/Program\ Files/Java/jdk1.6.0_03/include/win32/ -o InvocationTest InvocationTest.c Of course, in a real application, you'll want to dynamically locate the Java directory; look at launcher/java_md.c inside src.zip for inspiration.