Error while creating JVM -Urgent

Question

This is my Java program - Prog.java
public class Prog {
public static void main(String[] args) {
System.out.println("Hello World" + args[0]);
This is my c program --invoke.c
include <jni.h>
#ifdef _WIN32
#define PATH_SEPARATOR ';'
#else /* UNIX */
#define PATH_SEPARATOR ':'
#endif
#define USER_CLASSPATH "." /* where Prog.class is */
main() {
JNIEnv *env;
JavaVM *jvm;
JDK1_1InitArgs vm_args;
jint res;
jclass cls;
jmethodID mid;
jstring jstr;
jobjectArray args;
char classpath[1024];
/* IMPORTANT: specify vm_args version # if you use JDK1.1.2 and beyond */
vm_args.version = 0x00010001;
JNI_GetDefaultJavaVMInitArgs(&vm_args);
/* Append USER_CLASSPATH to the end of default system class path */
sprintf(classpath, "%s%c%s",
vm_args.classpath, PATH_SEPARATOR, USER_CLASSPATH);
vm_args.classpath = classpath;
/* Create the Java VM */
res = JNI_CreateJavaVM(&jvm,&env,&vm_args);
if (res < 0) {
fprintf(stderr, "Can't create Java VM\n");
exit(1);
cls = (*env)->FindClass(env, "Prog");
if (cls == 0) {
fprintf(stderr, "Can't find Prog class\n");
exit(1);
mid = (*env)->GetStaticMethodID(env, cls, "main", "([Ljava/lang/String;)V");
if (mid == 0) {
fprintf(stderr, "Can't find Prog.main\n");
exit(1);
jstr = (*env)->NewStringUTF(env, " from C!");
if (jstr == 0) {
fprintf(stderr, "Out of memory\n");
exit(1);
args = (*env)->NewObjectArray(env, 1,
(*env)->FindClass(env, "java/lang/String"), jstr);
if (args == 0) {
fprintf(stderr, "Out of memory\n");
exit(1);
(*env)->CallStaticVoidMethod(env, cls, mid, args);
(*jvm)->DestroyJavaVM(jvm);
I am compiling my program using this
gcc -I/usr/java/jdk1.3.1_06/include -I/usr/java/jdk1.3.1_06/include/linux -L/usr/java/jdk1.3.1_06/jre/lib/i386 -ljava invoke.c
All the paths and classpath is correct.
But I am getting an error
invoke.c: In function `main':
invoke.c:34: warning: passing arg 2 of `JNI_CreateJavaVM' from incompatible pointer type
Please tell me what could be the problem.
Thanks and Regarsd,
Anand

Answer 1

Hi Anandabrata,
I think you had referred to the following link
http://java.sun.com/docs/books/jni/html/invoke.html
But you had forgotten to note in which version you are going to invoke the JVM.
Since your compiling command refers to include paths as
======
gcc -I/usr/java/jdk1.3.1_06/include -I/usr/java/jdk1.3.1_06/include/linux -L/usr/java/jdk1.3.1_06/jre/lib/i386 -ljava invoke.c
======
I think you should be using jdk1.3XXXX some thing.
So, the JNI version that you should have tried should be Version2.
As I have commented the release that is specific to the version check and that of version1, better use the uncommented code and try creating the JavaVM.
You should be getting it right.
To be more specific
Do use this
// #ifdef JNI_VERSION_1_2
JavaVMInitArgs vm_args;
JavaVMOption options[1];
options[0].optionString =
"-Djava.class.path=" USER_CLASSPATH;
vm_args.version = 0x00010002;
vm_args.options = options;
vm_args.nOptions = 1;
vm_args.ignoreUnrecognized = JNI_TRUE;
/* Create the Java VM */
res = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);
// #else
// JDK1_1InitArgs vm_args;
// char classpath[1024];
// vm_args.version = 0x00010001;
// JNI_GetDefaultJavaVMInitArgs(&vm_args);
// /* Append USER_CLASSPATH to the default system class path */
// sprintf(classpath, "%s%c%s",
// vm_args.classpath, PATH_SEPARATOR, USER_CLASSPATH);
// vm_args.classpath = classpath;
// /* Create the Java VM */
// res = JNI_CreateJavaVM(&jvm, &env, &vm_args);
// #endif /* JNI_VERSION_1_2 */
Good Luck
Dhamo