Why my Invocation API failed?

Question

I want to call Java in my C program,but I failed in my beginning.this is my simple code:
#include "jni.h"
#include "stdio.h"
int main() {
JavaVMOption options[2];
JavaVMInitArgs vm_args;
JavaVM *jvm;
JNIEnv *env;
long status;
options[0].optionString = "-Djava.class.path=.";
options[1].optionString = "-verbose:jni";
memset(&vm_args, 0, sizeof(vm_args));
vm_args.version = JNI_VERSION_1_4;
vm_args.nOptions = 2;
vm_args.options = options;
status = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);
if (status == JNI_ERR) {
printf("Can't create Java VM\n");
else {
printf("SUCCESS\n");
return 0;
the code pass the compiling,but when run,it always display:
Can't create Java VM
why?
My JDK is in JBuilder9,and have jvm.dll file,one in E:\JBuilder9\jdk1.4\jre\bin\client,another in
E:\JBuilder9\jdk1.4\jre\bin\server.and one is 1.1M,another is 2.7M.which one is right?

Answer 1

Hallo,
This topic has been discussed several times in this forum. Try searching the forum for JNI_CreateJavaVM[i]. The following code worked for me:
   JavaVMInitArgs vm_argsNew;
   vm_argsNew.version = JNI_VERSION_1_2;
   JavaVMOption options[3];
   options[0].optionString = "-verbose:gc";
   sprintf (classpath, "-Djava.class.path=%s", USER_CLASSPATH);
   options[1].optionString = classpath;
   options[2].optionString = "-Djava.compiler=NONE";
   vm_argsNew.options = options;
   vm_argsNew.nOptions = 3;
   vm_argsNew.ignoreUnrecognized = JNI_TRUE;
   /* Create the Java VM */
   void ** ppEnvVoid = reinterpret_cast <void **> (&a_pJNIenv);
   jint rc = JNI_CreateJavaVM(&a_pjvm, ppEnvVoid, &vm_argsNew);
    if (rc < 0)
       printf ("CreateJavaVm Failed\n");
       return RC_ERROR;
    }Unfortunately, the return codes from JNI_CreateJavaVM are not very informative! You need to keep playing until it works. I suspect that the [i]ignoreUnrecognized option could be important!